At Epsom Sir Ivor was made 4/5 favourite for the Derby. Held up in the early stages by Piggott, he turned into the straight in seventh place. In the final furlong, he produced what the "Glasgow Herald" described as an "electrifying surge" of speed on the outside to catch the leader Connaught well inside the final furlong and win by one and a half lengths. After the race, Piggott described Sir Ivor as "the best I have ridden." Sir Ivor had now won six races in succession, but his run of success ended in his next race, as he was beaten two lengths by Ribero in the Irish Derby. He was then matched against 1967 Derby winner Royal Palace in the Eclipse Stakes at Sandown. In a closely contested race, Sir Ivor finished third, beaten a short head and three quarters of a length by Royal Palace and Taj Dewan. Both Piggott and O'Brien blamed the firm ground for Sir Ivor's defeat. He was then rested for an autumn campaign.