2002: two-year-old season

Yesterday began her racing career in the Listed Fillies' Sprint Stakes at Naas Racecourse on 3 June in which she finished eighth of the eleven runners behind the British challenger Rag Top. Later that month she started 1/2 favourite for a seven furlong maiden race at Tipperary Racecourse and won "comfortably" by two lengths from Encircle.^[8] The filly was then stepped up in class and started 5/4 favourite for the Group Three Debutante Stakes at the Curragh in August but was beaten into second by the 14/1 outsider Rainbows For All.

After a break of almost two month Yesterday was sent to France for the Group One Prix Marcel Boussac over 1600 metres at Longchamp Racecourse on 6 October. After turning into the straight in third place she was outpaced in the closing stages and finished sixth of the ten runners behind Six Perfections. Less than two weeks later she appeared at Newmarket Racecourse in England to contest the Rockfel Stakes and finished third behind Luvah Girl and Casual Look. On her final appearance of the year Yesterday was matched against male opposition in the Listed Eyrefield Stakes over nine furlongs on heavy ground at Leopardstown Racecourse on 10 November. Starting the 6/4 favourite in an eighteen-runner field she took the lead a furlong from the finish and accelerated away from her rivals to win "easily" by four lengths.^[9] Her win meant that Kinane clinched his 12th Irish Champion Jockey title.^[10]

2003: three-year-old season

Yesterday began her second season in the 1000 Guineas over the Rowley Mile at Newmarket on 4 May in which she started a 20/1 outsider and finished eighth of the nineteen runners as Russian Rhythm won from Six Perfections, Intercontinental and Soviet Song. Three weeks later at the Curragh Yesterday was one of eight fillies to contest the Irish 1000 Guineas and started the 11/2 second choice in the betting behind Six Perfections who was made the odds-on favourite. The other runners included Walayef (Round Tower Stakes, Athasi Stakes), Dimitrova (Leopardstown 1,000 Guineas Trial Stakes), Luminata (Silver Flash Stakes) and Cat Belling (Derrinstown Stud 1,000 Guineas Trial). Yesterday raced in fourth place as L'Ancresse set the pace before Dimitrova went to the front two furlongs from the finish. She overtook Dimitrova inside the final furlong and held off the late challenge of Six Perfections to win by a short head.^[11] The runner-up appeared somewhat unfortunate as her jockey Johnny Murtagh was unable to obtain a clear run until the final strides.^[12] Aidan O'Brien commented "Mick's ride was perfection. Yesterday stops when she hits the front but he couldn't wait any longer than he did. She goes on fast ground but she does like an ease. She will go for the Oaks". Kinane said, "Some days the luck bounces for you and some days it doesn't. Johnny found himself in one of those positions today. But in fairness to Yesterday, she did everything right".^[13]

On 6 June Yesterday was moved up in distance and started 100/30 favourite for the 225th running of the Oaks Stakes over one and a half miles at Epsom Downs Racecourse. After being restrained in the early stages she attempted to move into contention in the straight but was repeatedly blocked and hampered before obtaining a clear run inside the final furlong. She finished strongly but failed by a neck to peg back Casual Look, appearing to be an unlucky loser.^[14][15] The Irish Times's correspondent stated that she was "clearly the best filly in the race".^[16] In the Irish Oaks at the Curragh on 13 July she started the 11/8 favourite but finished fourth behind Vintage Tipple, L'Ancresse and Casual Look.

After a late summer break Yesterday was sent to France for the Group One Prix Vermeille over 2400 metres at Longchamp on 14 September. Ridden by Jamie Spencer she turned into the straight in fifth place and stayed on well but failed by a head to overhaul the Godolphin filly Mezzo Soprano. The filly was matched against older fillies and mares when she returned to Longchamp for the Prix de l'Opéra over 2000 metres on 5 October. She was held up at the back of the field before making a strong late run and finished second, beaten a head by the British-trained four-year-old Zee Zee Top with Bright Sky (winner of the race in 2002) a neck away in third. Yesterday was then sent to America for the Breeders' Cup Filly and Mare Turf at Santa Anita Park on 25 October in which she stayed on from the rear of the field to finish third behind Islington and L'Ancresse.^[17]

2004: four-year-old season

Yesterday remained in training as a four-year-old and was ridden by Spencer in all three of her starts. After an absence of more than ten months she returned in the Matron Stakes at Leopardstown on 11 September and finished fifth of the six runners behind Soviet Song. She then ran for the second time in the Prix de l'Opéra and finished fourth behind Alexander Goldrun. She ended her racing career with a second attempt at the Breeders Cup Filly & Mare Turf at Lone Star Park on 30 October and finished fifth behind Ouija Board in a twelve-runner field.