2000: two-year-old season

Dilshaan made his debut in a Novice race (for horses with no more than one previous win) over seven furlongs at Sandown Park Racecourse on 13 September 2000. Ridden by the veteran Pat Eddery in a five-runner field he started 7/2 third choice in the betting behind Attache and Gleaming Blade, both of whom had already won maiden races. He was slightly hampered when Gleaming Blade hung to the left in the last quarter mile but recovered to finish second, a length and a half behind Attache. Despite his defeat, the colt was then moved up sharply in class for the Group One Racing Post Trophy at Doncaster Racecourse on 21 October. He was ridden by Johnny Murtagh and started a 14/1 outsider in a field of ten juvenile colts. The Aidan O'Brien-trained Freud was made favourite, whilst the other contenders included Tamburlaine, Grandera, CD Europe (Coventry Stakes), Darwin, Bonnard (runner-up in the Futurity Stakes) and Dayglow Dancer (runner-up in the Prix de Condé). Dilshaan started slowly and Murtagh restrained him at the rear of the field before switching to the outside and beginning to make progress in the straight. Tamburlaine opened up a clear advantage in the last quarter mile, but Dilshaan continued to make ground, gained the advantage 100 yards from the finish and drew away to win by two and a half lengths. Bonnard was three quarters of a length behind Tamburlaine in third, five lengths clear of Darwin in fourth.^[7][8] Stoute responded to the colt's win by saying "I certainly wasn't confident he'd win but he was entitled to run well. He's done it really nicely and is a horse with a lot of scope. He's an interesting prospect and will need to go further than a mile next season".^[9]

2001: three-year-old season

Dilshaan began his second season in the Dante Stakes (a major trial race for the Epsom Derby) over ten and a half furlongs at York Racecourse on 16 May. He was made the 9/4 favourite against five opponents including Celtic Silence (Chesham Stakes), Olden Times (Feilden Stakes), Storming Home and Rosi's Boy (Newmarket Stakes). Ridden by Kieren Fallon he tracked the leaders as Celtic Silence set the pace before moving up to make his challenge two furlongs out. Dilshaan took the lead approaching the final furlong and stayed on well in the closing stages to win by half a length and a neck from Celtic Silence and Storming Home.^[10] The colt's success meant that Michael Stoute had two leading contenders for the Derby, having won the 2000 Guineas with Golan. The trainer commented "It was a good solid performance... I am delighted he has won and I feel he will make further progress... He's a very placid, likeable colt". Fallon said of the winner "I've always liked this fellow. The other morning I rode him in work and he was impressive. I thought he would come home alone here. He's gone to the front and done nothing... he was idling".^[11] The leading bookmakers responded by making him third favourite in the ante-post betting market for the Derby.^[12]

In the 2001 Epsom Derby on 9 June Dilshaan, ridden by Murtagh started the 5/1 fourth favourite behind Galileo, Golan and the Lingfield Derby Trial winner Perfect Sunday. After turning into the straight in fifth place he made no further progress and finished seventh of the twelve runners behind Galileo.

Dilshaan sustained a joint injury shortly after the Derby and missed the rest of the season. He remained in training as a four-year-old but suffered a recurrence of his previous injury and his retirement was announced in July 2002.^[13]