In Grand Slam competition he appeared in the main draw of all four major tournaments. He took Guillermo Vilas to five sets when he faced the Argentine in the second round of the 1983 US Open. With the score at 1–1 in the fifth set, Cain was injured when he twisted his ankle and slid head first into the scoreboard. Although he was able to continue the match he won only one more game.[5] In both of his appearances at Wimbledon he had to retire hurt during his first round matches, against Tim Gullikson in 1983 and Miloslav Mečíř in 1984.
Retiring from tennis in 1986, Cain then worked with Wheat First Securities for many years.[6] He is now Senior Vice-President with UBS Financial Services and is married with two daughters and a son.