NEW HAVEN, May 14--Dale Junta led an inspired Crimson tennis squad to a tremendous 6-3 upset victory over previously undefeated Yale yesterday, beating Don Dell at first singles and then teaming up with Larry Sears to take the first doubles match.

The win carried the varsity to the Eastern League championship, although Yale's depth enabled the Elis to win the Big Three crown, capturing five of the six additional contests.

Coach Jack Barnaby said afterwards that it was "the best win any team of mine ever had, and I've been coaching for 26 years." The victory gave the Crimson a 16-3 overall record and turned a very good season into a great one. It was the third straight Crimson win over the Bulldogs.

In his match with Dell, Junta was spectacular. Almost completely recovered from an early season back injury, he bounced back from a 1-3 deficit in the deciding third set to take the next five games and win the tense contest.

In the first set, Dell never had a chance, as Junta achieved three break-throughs, holding his own service easily to win, 6-1. Dell, however, rallied in the fourth game of the next set, when, trailing 1-2, he held his service after Junta had picked up a 40-15 advantage. The lean Yale sophomore took the next four games and the set, 6-2. When he jumped away to a 3-1 lead in the third set, it looked as though he would go all the way. But Junta refused to quit, and, calling on reserve amazing for one who was playing for only the fourth time since April, simply outclassed his favored opponent to triumph, 6-3.

Larry Sears was the only straight set victor of the afternoon, as he polished off Jon Clark at number two, 6-4, 6-3. Especially impressive were Sears' backhand passing shots and crisp drop shots.

The other two singles wins were registered by Tim Gall-wey and Al Goldman. The former upset Gene Scott, who had not lost a match all year, by breaking through in the eighth game of the third set to triumph, 6-3, 3-6, 6-4.

Goldman's win was a richly deserved one. In upsetting Sandy Wiener, he also downed a previously unbeaten opponent. After taking the long first set, 9-7, he dropped the second in love before finishing strongly with a 6-2 margin in the third.

Ned Weld and Fred Vinton both lost, but not without showing the same hustle and drive that characterized the team effort. Tom Freiberg downed Weld, 6-3 9-7, and Sam Schoon-maker beat Vinton, 6-2, 7-5.

It was the doubles matches which decided the outcome of both the League and Big Three standings. By winning the first two, the Crimson gained a decisive League victory, but since the seventh, eighth, and ninth singles matches went to Yale, the Elis' victories in the last four doubles carried them to the Big Three crown.

Both Junta and Sears and Vinton and Gallwey played inspired tennis to win. The first pair won, 8-6, 3-6, 6-3, and about an hour later, the second pair triumphed, 5-7, 17-15, 9-7.