1981: two-year-old season

After finishing fourth over five furlongs on his racecourse debut Cajun was moved up in class and distance for the Chesham Stakes over six furlongs at Royal Ascot in June. He took the lead in the last quarter mile and looked likely to win easily but had to be driven out to hold of the late challenge of Treboro by three quarters of a length. He was strongly fancied for the July Stakes at Newmarket Racecourse but after being restrained in the early stages he finished fifth of the eleven runners behind the Barry Hills-trained End of the Line. In the Richmond Stakes at Goodwood Racecourse three weeks later he produced a better effort to finish second by a neck to Tender King, with End of the Line in third place. Cajun was then stepped up in distance for the Seaton Delaval Stakes over seven furlongs at Newcastle Racecourse. He looked certain to win easily when he joined the leaders two furlongs from the finish but failed to make any further progress and finished third behind Zilos and Telephone Man. He was then dropped in class for a minor event over six furlongs at Windsor Racecourse in September. After leading from the start he began to struggle in the final furlong and was beaten a neck by the filly Epithet.^[3]

Following four consecutive defeats Cajun was moved up to Group One level and started a 20/1 outsider for the Middle Park Stakes at Newmarket on 1 October. Tender King and End of the Line were again in opposition, whilst the other nine runners included Hays (winner of the Mill Reef Stakes), Peterhof (Flying Childers Stakes), Chiris's Lad (runner-up in the Coventry Stakes), Take the Floor (runner-up in the Gimcrack Stakes) and Philip Martin (third in the National Stakes). Ridden by Lester Piggott, Cajun raced at the rear of the field as the 66/1 outsider Lucky Hunter set the pace. but began to make rapid progress approaching the final furlong. He went to the front in the closing stages and won by three quarters of a length from Lucky Hunter with Wattlefield a neck away in third. Cecil was summoned by the racecourse stewards to explain the improvement in Cajun's form and said that the colt was difficult, had hesitated in his run at Windsor and performed much better than expected up the Newmarket hill.^[3]

1982: three-year-old season

On his three-year-old debut, Cajun contested the Greenham Stakes (a major trial race for the 2000 Guineas) over seven furlongs at Newbury Racecourse in April. Ridden by Piggott he started at odds of 7/2 and won by half a length from Tender King. On 15 May the colt started 4/1 second favourite for the Irish 2,000 Guineas at the Curragh but finished ninth of the fourteen runners behind Dara Monarch. Later that month he started odd-on favourite for the Gus Demmy Memorial stakes over six furlongs at Haydock Park but finished third behind Not For Show and Vaigly Star. At Royal Ascot in June he finished unplaced behind Fearless Lad in the King's Stand Stakes. After a break of almost three months he returned in the Park Stakes at Doncaster Racecourse in September. As in some of his previous races he looked a likely winner but found little when put under pressure and finished third to The Quiet Bidder and Merlin's Charm. On his final appearance of the year he was equipped with blinkers for the Diadem Stakes at Ascot. He reportedly showed little interest in the race and finished unplaced behind Indian King.^[2]