2008–2010: Junior Career and Turning Pro

Ramanathan began playing tennis at the age of five, turning professional in 2009.

2014–2016: Early career

In 2014, Ramanathan qualified for the main draw of the Chennai Open and beat the then-Indian No. 1 Somdev Devvarman in the first round.^[6][7][8] He then lost to Marcel Granollers in the second round.

In 2015, Ramanathan played mostly on Futures and Challenger level. He entered the Chennai Open, where he lost in first round to Tatsuma Ito in straight sets.^[3] In April, he reached his first doubles final at a challenger event at the Mersin Cup in Turkey. Partnering with Riccardo Ghedin, the pair lost the final to Mate Pavić and Michael Venus.^[9] He entered his second ATP world tour event of the year at Malaysian Open where he lost in the first round to Mikhail Kukushkin.^[3]

Ramanathan at the 2016 Wimbledon Men's Qualifiers

In the 2016 season, Ramanathan entered the Chennai Open and reached the quarterfinals, his best result at an ATP World Tour event. He defeated Daniel Gimeno Traver and Alexander Kudryavtsev in the first and second rounds respectively. He lost to Aljaž Bedene in the quarterfinals.^[10] In October, Ramanathan partnered with Jeevan Nedunchezhiyan. The pair reached the final at the Vietnam Open Challenger, where they lost to Sanchai Ratiwatana and Sonchat Ratiwatana.^[11]

2017: Challenger breakthrough, first ATP top-10 win

In April, Ramanathan reached his first singles challenger final at the Tallahassee challenger. He lost to Blaž Rola.^[12]

Ramanathan entered the 2017 Antalya Open, where he upset world No. 8 and top seed Dominic Thiem in the second round. This was his first match against a top-10 player. Ranked world No. 222, Ramanathan defeated Thiem in straight sets, 6–3, 6–2.^[13] He progressed to the quarterfinals, where he lost to Marcos Baghdatis.

In July, he reached his second singles challenger final at Nielsen Pro Tennis Championships. He lost in straight sets to Akira Santillan.^[14][15]

In August, Ramanathan qualified for the first time in main draw of a Masters 1000 tournament at Cincinnati Masters. He defeated Christopher Eubanks in first round, but lost to Jared Donaldson in second round.^[16] Ramanathan entered qualifying draw of US Open. He defeated Paul-Henri Mathieu in first round but lost to Nicolas Mahut in second round.^[17] He finished year with singles ranking of 148.

2018: Hall of Fame Tennis Championships finalist

Ramanathan opened his new season by entering Maharashtra Open as a wild card. He lost in round 2 to top seed Marin Cilic in straight sets.^[18] He then entered qualifying draw of Australian Open where he lost in final qualifying round to Vasek Pospisil.^[19]

In April, Ramanathan reached his first challenger singles final of the season at Taipei Challenger. He was defeated in the finals by compatriot Yuki Bhambri.^[20]

In July, Ramanathan reached his first ATP final at Newport, where he lost to Steve Johnson. He became the first Indian to reach an ATP world tour singles final since Somdev Devvarman at the 2011 Johannesburg Open.^[21]

In November, he won his first doubles ATP Challenger title at Pune Challenger. He paired with compatriot Vijay Sundar Prashanth and defeated Hsieh Cheng-peng and Yang Tsung-hua in the final.^[22] He finished the year with singles ranking of 133.

2019–20: Singles final & four doubles titles in Challengers

Ramanthan won the doubles titles in Japan, France, Italy, and two in India.^[23]

2021: Major debut in mixed doubles, Maiden singles Challenger title

Ramanathan entered men's singles qualifying draw of Wimbledon. He defeated Jozef Kovalík and Tomás Martín Etcheverry in the first and second rounds respectively in straight sets but lost to Marc Polmans in last qualifying round in a five sets thriller in the tiebreaker. He made his Grand Slam main draw debut in mixed doubles where he entered the draw after a last minute withdrawal partnering Ankita Raina. This was a Grand Slam mixed doubles debut for both players. They lost to compatriots Rohan Bopanna and Sania Mirza in straight sets. It was a historic first ever all Indian match at a Grand Slam level.

He won his first singles Challenger title at Manama Challenger where he defeated Evgeny Karlovskiy in straight sets.^[24] Ramanathan ended 2021 year by reaching the quarterfinals of the 2021 Antalya Challenger III in singles and the semifinals of doubles with Vladyslav Orlov.

2022: First ATP Tour title & Top 100 debut in doubles

Ramkumar had good start to 2022 season with a title win in Adelaide, Ramanathan partnered with Rohan Bopanna and won the title by defeating top seeds Ivan Dodig and Marcelo Melo in the final. This was his first ATP Tour title. Just a month later he won his second ATP title with Rohan Bopanna at Maharastra Open by defeating Australian pair of Luke Saville and John-Patrick Smith in the final. Following his title victory he broke into ATP Top 100 doubles rankings by reaching career best ranking of World No. 94.^[25][26] Whereas he lost to Holger Rune in Adelaide qualifiers and Gian Marco Moroni in Australian Open qualifiers in straight sets respectively. He had also lost to Stefano Travaglia in Maharashtra first round in three sets.

Ramanathan lost in the first round of 2022 Bengaluru Open to Max Purcell in three sets but went on to win the doubles title with Saketh Myneni seeded no.3 defeating French pair of Hugo Grenier and Alexandre Müller in straight sets in the final. The pair didn't drop a single set in winning the title. He then lost to Mathias Bourgue at Bengaluru Open 2 but reached the doubles final with Saketh Myneni again losing to Arjun Kadhe and Alexander Erler in the tie breaker. Ramanathan and Saketh lost in the 1st round of 2022 Dubai Tennis Championships to John Peers and Filip Polášek in straight sets after receiving a wildcard.

Ramanathan lost to Liam Broady in the qualifying round of 2022 Indian Wells Masters. Ramanathan was the top seed in the singles qualifying round of 2022 Challenger di Roseto degli Abruzzi II but lost to Francesco Maestrelli. He reached the quarterfinals of the doubles event with Jeevan Nedunchezhiyan. He then reached the final of the Challenger Biel/Bienne with Purav Raja where they lost to top seeds Pierre-Hugues Herbert and Albano Olivetti in straight sets. He then lost to JC Aragone in the first round of Salinas Challenger. As the top seeds with Jeevan in doubles, he still lost to eventual champions and compatriots Yuki Bhambri and Saketh Myneni.

Singles: 1 (1 runner-up)

Result	W–L	Date	Tournament	Tier	Surface	Opponent	Score
Loss	0–1	Jul 2018	Hall of Fame Tennis Championships, United States	250 Series	Grass	Steve Johnson	5–7, 6–3, 2–6

Doubles: 2 (2 titles)

Result	W–L	Date	Tournament	Tier	Surface	Partner	Opponents	Score
Win	1–0	Jan 2022	Adelaide International, Australia	250 Series	Hard	Rohan Bopanna	Ivan Dodig Marcelo Melo	7–6(8–6), 6–1
Win	2–0	Jan 2022	Maharashtra Open, India	250 Series	Hard	Rohan Bopanna	Luke Saville John-Patrick Smith	6–7(10–12), 6–3, [10–6]

Singles: 30 (18–12)

Result	W–L	Date	Tournament	Tier	Surface	Opponent	Score
Loss	0–1	Dec 2012	India F16, Dharwad	Futures	Hard	Sanam Singh	2–6, 6–7(4–7)
Loss	0–2	Jun 2013	Spain F17, Martos	Futures	Hard	Steven Diez	5–7, 7–6(7–4), 4–6
Win	1–2	Nov 2013	India F11, Raipur	Futures	Hard	Lee Duck-hee	3–6, 7–6(8–6), 6–4
Win	2–2	Dec 2013	Cambodia F2, Phnom Penh	Futures	Hard	Josh Goodall	6–1, 4–6, 6–4
Win	3–2	May 2014	Turkey F14, Antalya	Futures	Hard	Anton Zaitcev	6–7(6–8), 6–0, 6–2
Win	4–2	Jul 2014	Spain F17, Getxo	Futures	Clay	Marc Giner	6–4, 6–1
Loss	4–3	Jul 2014	Spain F18, Gandia	Futures	Clay	Arthur De Greef	4–6, 6–4, 3–6
Win	5–3	Sep 2014	Turkey F32, Antalya	Futures	Hard	Rémi Boutillier	6–4, 7–6(10–8)
Win	6–3	Sep 2014	Turkey F33, Antalya	Futures	Hard	Ricardo Rodríguez	6–3, 6–0
Win	7–3	Nov 2014	India F7, Raipur	Futures	Hard	Saketh Myneni	6–1, 6–2
Loss	7–4	Dec 2014	Qatar F5, Doha	Futures	Hard	Nikoloz Basilashvili	6–7(5–7), 2–6
Loss	7–5	Mar 2015	India F3, Tiruchirapalli	Futures	Clay	Vijay Sundar Prashanth	3–6, 4–6
Win	8–5	May 2015	India F6, Mysore	Futures	Hard	Vishnu Vardhan	7–6(7–2), 3–6, 6–3
Win	9–5	Sep 2015	India F13, Coimbatore	Futures	Hard	Ouyang Bowen	6–4, 6–2
Loss	9–6	Oct 2015	Turkey F40, Antalya	Futures	Hard	Tim van Rijthoven	3–6, 6–4, 4–6
Win	10–6	Nov 2015	India F16, Gwalior	Futures	Hard	Prajnesh Gunneswaran	6–3, 6–4
Win	11–6	Dec 2015	India F19, Mumbai	Futures	Hard	Prajnesh Gunneswaran	6–3, 6–3
Win	12–6	May 2016	Spain F12, Lleida	Futures	Clay	Félix Auger-Aliassime	7–6(7–1), 6–2
Win	13–6	Dec 2016	Qatar F5, Doha	Futures	Hard	Sebastian Ofner	7–5, 6–3
Win	14–6	Dec 2016	Qatar F6, Doha	Futures	Hard	Sebastian Ofner	7–5, 6–3
Loss	14–7	Apr 2017	Tallahassee, USA	Challenger	Clay	Blaž Rola	2–6, 7–6(8–6), 5–7
Win	15–7	Jun 2017	Singapore F2, Singapore	Futures	Hard	Raymond Sarmiento	6–2, 6–2
Win	16–7	Jun 2017	Singapore F3, Singapore	Futures	Hard	Nicholas S. Hu	7–6(7–4), 6–2
Loss	16–8	Jul 2017	Winnetka, USA	Challenger	Hard	Akira Santillan	6–7(1–7), 2–6
Loss	16–9	Nov 2017	Pune, India	Challenger	Hard	Yuki Bhambri	6–4, 3–6, 4–6
Loss	16–10	Apr 2018	Taipei, Chinese Taipei	Challenger	Hard (i)	Yuki Bhambri	3–6, 4–6
Loss	16–11	Nov 2020	Eckental, Germany	Challenger	Carpet (i)	Sebastian Korda	4–6, 4–6
Loss	16–12	Jul 2021	Cary, USA	Challenger	Hard	Mitchell Krueger	6–7(4–7), 2–6
Win	17–12	Nov 2021	Manama, Bahrain	Challenger	Hard	Evgeny Karlovskiy	6–1, 6–4
Win	18–12	Oct 2023	M25 Dharwad, India	World Tour	Hard	Digvijay Pratap Singh	7–6(7–5), 7–6(8–6)

Doubles: 43 (22–21)

Result	W–L	Date	Tournament	Tier	Surface	Partner	Opponents	Score
Win	1–0	Aug 2011	Spain F29, Vigo	Futures	Clay	Rafael Mazón-Hernández	Taro Daniel Hiroyasu Ehara	6–3, 6–2
Win	2–0	Jul 2012	Turkey F28, İzmir	Futures	Clay	Kirill Dmitriev	Julien Demois Yanais Laurent	6–2, 6–2
Win	3–0	Jun 2013	Spain F17, Martos	Futures	Hard	Ashwin Vijayragavan	Roberto Ortega Olmedo Ricardo Villacorta-Alonso	6–3, 5–7, [11–9]
Loss	3–1	Sep 2013	Spain F32, Sevilla	Futures	Clay	Matwé Middelkoop	Eduard Esteve Lobato Oriol Roca Batalla	2–6, 3–6
Win	4–1	Oct 2013	Spain F33, Sabadell	Futures	Clay	David Pérez Sanz	Eduard Esteve Lobato Oriol Roca Batalla	6–7(4–7), 6–3, [10–8]
Loss	4–2	Oct 2013	Spain F36, El Prat de Llobregat	Futures	Clay	David Pérez Sanz	Antonio Campo Omar Giacalone	6–3, 4–6, [6–10]
Loss	4–3	Nov 2013	India F9, Delhi	Futures	Hard	Ashwin Vijayragavan	Sriram Balaji Ranjeet Virali-Murugesan	6–7(3–7), 3–6
Loss	4–4	Nov 2013	India F11, Raipur	Futures	Hard	Mohit Mayur Jayaprakash	Sriram Balaji Ranjeet Virali-Murugesan	1–6, 3–6
Win	5–4	Dec 2013	Cambodia F3, Phnom Penh	Futures	Hard	Karunuday Singh	Takuto Niki Arata Onozawa	6–4, 6–3
Win	6–4	Mar 2014	India F4, Trichy	Futures	Clay	Arun-Prakash Rajagopalan	Giorgio Portaluri Lucas Renard	6–3, 4–6, [10–6]
Loss	6–5	May 2014	Turkey F14, Antalya	Futures	Hard	Andrei Ciumac	Sho Katayama Bumpei Sato	3–6, 1–6
Loss	6–6	May 2014	Turkey F16, Antalya	Futures	Hard	Hugo Grenier	Dimitar Kuzmanov Ricardo Rodríguez	w/o
Win	7–6	Jun 2014	Spain F15, Palma del Río	Futures	Hard	Jaume Pla Malfeito	Eduard Esteve Lobato Oriol Roca Batalla	7–6(7–2), 4–6, [10–7]
Win	8–6	Jul 2014	Spain F17, Getxo	Futures	Clay	David Pérez Sanz	João Domingues José Antón Salazar Martín	5–7, 6–3, [10–4]
Loss	8–7	Jul 2014	Spain F18, Gandia	Futures	Clay	Miguel Ángel Reyes-Varela	Juan-Samuel Arauzo-Martínez Martin Beran	6–2, 6–7(3–7), [9–11]
Loss	8–8	Sep 2014	Turkey F33, Antalya	Futures	Hard	Ricardo Rodríguez	Scott Clayton Richard Gabb	5–7, 6–7(7–9)
Win	9–8	Oct 2014	Turkey F34, Antalya	Futures	Hard	Tuna Altuna	Barış Ergüden Jan Hájek	6–4, 6–2
Win	10–8	Dec 2014	Qatar F5, Doha	Futures	Hard	Sriram Balaji	Sam Barry Maximilian Neuchrist	6–3, 6–4
Loss	10–9	Mar 2015	India F2, Bhimavaram	Futures	Hard	Ranjeet Virali-Murugesan	Sriram Balaji Vishnu Vardhan	7–6(7–5), 3–6, [6–10]
Win	11–9	Mar 2015	India F3, Tiruchirappalli	Futures	Clay	Arun-Prakash Rajagopalan	Anvit Bendre Akash Wagh	3–6, 6–2, [10–6]
Loss	11–10	Apr 2015	Mersin, Turkey	Challenger	Clay	Riccardo Ghedin	Mate Pavić Michael Venus	7–5, 3–6, [4–10]
Win	12–10	Oct 2015	Turkey F41, Antalya	Futures	Hard	Sarp Ağabigün	Kirill Dmitriev Luca Margaroli	6–4, 6–4
Loss	12–11	Nov 2015	India F16, Gwalior	Futures	Hard	Hung Jui-chen	Sriram Balaji Vishnu Vardhan	4–6, 6–7(5–7)
Win	13–11	Dec 2015	India F19, Mumbai	Futures	Hard	Kaliyanda Poonacha	Anvit Bendre Chandril Sood	6–4, 6–3
Win	14–11	May 2016	Spain F12, Lleida	Futures	Clay	David Vega Hernández	Carlos Boluda-Purkiss Alex de Minaur	6–3, 6–1
Loss	14–12	Oct 2016	France F21, Nevers	Futures	Hard (i)	Jordi Muñoz Abreu	Antoine Hoang Grégoire Jacq	3–6, 4–6
Loss	14–13	Oct 2016	Ho Chi Minh City, Vietnam	Challenger	Hard	Jeevan Nedunchezhiyan	Sanchai Ratiwatana Sonchat Ratiwatana	5–7, 4–6
Win	15–13	Feb 2017	USA F8, Indian Harbour Beach	Futures	Clay	Jaume Pla Malfeito	Hunter Callahan Nick Chappell	6–2, 6–7(5–7), [11–9]
Loss	15–14	Mar 2017	USA F9, Orlando	Futures	Clay	Jaume Pla Malfeito	Connor Smith Rhyne Williams	4–6, 4–6
Loss	15–15	Nov 2018	Bratislava, Slovakia	Challenger	Hard (i)	Andrei Vasilevski	Denys Molchanov Igor Zelenay	2–6, 6–3, [9–11]
Win	16–15	Nov 2018	Pune, India	Challenger	Hard	Vijay Sundar Prashanth	Hsieh Cheng-peng Yang Tsung-hua	7–6(7–3), 6–7(5–7), [10–7]
Loss	16–16	Jun 2019	Surbiton, Great Britain	Challenger	Grass	Kwon Soon-woo	Marcel Granollers Ben McLachlan	6–4, 3–6, [2–10]
Win	17–16	Jul 2019	Recanati, Italy	Challenger	Hard	Gonçalo Oliveira	Andrea Vavassori David Vega Hernández	6–2, 6–4
Loss	17–17	Oct 2019	Barcelona, Spain	Challenger	Clay	Sergio Martos Gornés	Simone Bolelli David Vega Hernández	4–6, 5–7
Loss	17–18	Nov 2019	Shenzhen, China	Challenger	Hard	Mikhail Elgin	Hsieh Cheng-peng Yang Tsung-hua	2–6, 5–7
Win	18–18	Nov 2019	Kobe, Japan	Challenger	Hard (i)	Purav Raja	André Göransson Christopher Rungkat	7–6(8–6), 6–3
Win	19–18	Nov 2019	Pune, India	Challenger	Hard	Purav Raja	Arjun Kadhe Saketh Myneni	7–6(7–3), 6–3
Win	20–18	Feb 2020	Bangalore, India	Challenger	Hard	Purav Raja	Leander Paes Matthew Ebden	6–0, 6–3
Win	21–18	Sep 2021	Cassis, France	Challenger	Hard	Sriram Balaji	Hans Hach Verdugo Miguel Ángel Reyes-Varela	6–4, 3–6, [10–6]
Win	22–18	Feb 2022	Bangalore, India	Challenger	Hard	Saketh Myneni	Hugo Grenier Alexandre Müller	6–3, 6-2
Loss	22–19	Feb 2022	Bangalore, India	Challenger	Hard	Saketh Myneni	Alexander Erler Arjun Kadhe	3-6, 7-6(7-4), [7-10]
Loss	22–20	Mar 2022	Biel/Bienne, Switzerland	Challenger	Hard (i)	Purav Raja	Pierre-Hugues Herbert Albano Olivetti	3-6, 4-6
Loss	22–21	June 2022	Ilkley, UK	Challenger	Grass	John-Patrick Smith	Julian Cash Henry Patten	5-7, 4-6