As a two-year-old he showed great promise at home but refused to enter the starting stalls on his scheduled debut before finishing fifth in the Observer Gold Cup.
In 1968 he ran poorly in the 2000 Guineas but proved himself a top-class colt by running second to Sir Ivor in The Derby after looking likely to win entering the final furlong.
He was scheduled to make his debut in the Convivial Maiden Stakes at York Racecourse in August 1967 but refused to enter the starting stalls and was withdrawn from the race.
In October he was entered in the Observer Gold Cup at Doncaster Racecourse (the most valuable event for two-year-olds run in Britain) and finished fifth behind Vaguely Noble.
[6] Connaught made good progress in the winter of 1967/1968 and was expected to run well in his seasonal debut in the Greenham Stakes but again refused to enter the stalls and did not take part.
Despite his temperamental problems he was well backed for the 2000 Guineas and started at odds of 13/2 but after showing good speed in the early stages he faded to finish ninth of the ten runners behind Sir Ivor.
In the straight, the colt opened up a clear lead over his opponents and looked certain to win before Lester Piggott produced Sir Ivor with a late run on the outside.
Commenting on the race more than forty years later, Barclay said "The Derby on Connaught was a shattering, bone-crushing moment but, to finish so close, still opened a lot of doors for a 20-year-old.
[5] At Royal Ascot, later in June he started the 1/2 favourite[7] for the King Edward VII Stakes and recorded his first win, beating Ribero by twelve lengths.
[6] At Royal Ascot he started 11/10 favourite[7] for the ten furlong Prince of Wales's Stakes and won by five lengths from Wolver Hollow, breaking the track record by four seconds.
[10] Connaught was retired from racing to become a breeding stallion and produced a steady stream of stakes winners before being pensioned from stud duty in the mid 1980s.