Thorburn was runner-up in two other World Championships, losing 21–25 to John Spencer in the 1977 final and 6–18 to Steve Davis in the 1983 final. One of his most celebrated moments came during his second-round encounter with Terry Griffiths in 1983, when he became the first player to compile a maximum break in a World Championship match. He was the second player, after Davis, to make a televised 147 break in professional competition.