In the spring of 1989, reports of impressive work at home saw Nashwan's odds for
Classic Races continually shorten, and when he began his three-year-old campaign in the
General Accident 2000 Guineas at
Newmarket on 6 May, he started the race as 3/1 favourite. He took the lead approaching the final quarter mile and won by a length, with
Exbourne in second and
Danehill a further half length behind in third. A month later, Nashwan was moved up in distance for the
Ever Ready Derby over one and a half miles at
Epsom Downs Racecourse. Despite the unseasonably cold, damp weather, the race attracted an estimated 500,000 spectators including
Queen Elizabeth II. Nashwan started 5/4 favourite against eleven opponents, with the biggest danger expected to come from Cacoethes, winner of the
Lingfield Derby Trial. Carson positioned the favourite just behind the leaders before moving up to take the lead from Cacoethes in the straight. He pulled "effortlessly" clear in the closing stages to win by five lengths from the 500/1 outsider
Terimon, who finished well to deprive Cacoethes of second. He was the first horse to complete the Guineas-Derby double since
Nijinsky II in 1970, Nashwan took the lead approaching the final furlong and won by five lengths from the outsider
Opening Verse, who later won the
Breeders' Cup Mile. Two weeks later, Nashwan contested Britain's most prestigious all-aged race, the
King George VI and Queen Elizabeth Stakes over one and a half miles at Ascot. With the late withdrawal of
Prix du Jockey Club winner
Old Vic, Nashwan was expected to win easily and started as 2/9 favourite. This time he had to fight for his victory, with old rival Cacoethes challenging him throughout the final two furlongs. Nashwan was driven out by Carson to win by a neck, with the subsequent
Prix de l'Arc de Triomphe winner Carroll House a further eleven lengths back in fifth. His narrow margin of victory led some critics to question his status as a "super-horse". Nashwan's owner decided not to attempt the
Triple Crown in the
St Leger Stakes, and the colt was instead aimed at the Prix de l'Arc de Triomphe at
Longchamp in October. To prepare for this race, he was sent to the
Prix Niel over the Arc course and distance on 17 September. Racing on soft ground, Nashwan moved up to challenge in the straight but made no further progress and finished third, beaten one and a half lengths and half a length by the French-trained colts
Golden Pheasant and French Glory. Neither Hern nor Carson could offer any explanation for the "lifeless" performance, with the jockey commenting that the 1/5 favourite "didn't have any energy". Nashwan missed the Arc, and, as had been announced in summer, he was retired from racing at the end of the year. ==Assessment==