Colin Adair became the first foreigner to win the U.S. singles squash championship in 15 years when he defeated fellow Canadian Peter Martin yesterday in Harvard's Hemenway Gymnasium 11-15, 15-11, 15-9, and 15-13.

Adair, who had been very solemn during all of his tournament matches went wild with emotion after clinching the title. "If I had lost this one" he said "I would have jumped out of the window."

Harvard sophomore Larry Terell provided the biggest upset of the three-day tournament by defeating second seeded Bob Heatherington of Pittsburgh 15-10, 15-8, 9-15, 11-15, 15-11. Heatherington was runnerup in last year's championship.

"This is the biggest win of my life" Terrell said after his victory. "My forehand and backhand drives were strong, my drop shots were effective, and I was running better which enabled me to stay in there when I was fooled," he added. Terrell lost in the quarter-finals to J. Smith Chapman of Montreal.

Anil Nayar, '69, Harvard's number one player, was eliminated in the second round by Martin, 15-9, 9-15, 15-9, 15-10. The victory was Martin's first decision over Nayar, the newly crowned Canadian title holder.

New York, which had earlier defeated Harvard, edged Philadelphia 3-2 to capture the team championship.