ITHACA, N.Y., Feb. 11--After losing a 12-point halftime lead, the Crimson rallied to upset Cornell 72-65 in overtime at Barton Hall tonight. The loss was the Big Red's third in Ivy play, and dropped them into third place behind Princeton and Yale. Harvard is now 2-5, and shares seventh place with Brown.

With its version of the Drake shuffle performing even better than last night against Columbia, the Crimson continually broke men free for easy lay-ups during their first half surge.

Pete Kelley's hook broke a 15-15 tie with 9 minutes left, and Gary Borchard and Joe Deering's shooting combined to give the Crimson a 37-25 lead at halftime.

Deering, who scored on eight of ten shots and finished with 17 points, tallied five baskets in the half, most coming from the pattern designed to pick off defenders on give and go plays.

Starting the second half, the late-game jitters that have plagued Harvard all season came again and Ron Ivkovich's long jump shot with 11:55 left tied the score at 46-46.

After a 53-53 deadlock Kelley's jump and two fouls by Vern Strand gave the Crimson a four point lend with four minutes remaining. Another pair of free throws, this time by Kelley, made the score 59-56 with 2:11 left, but Ivkovich reduced the lead to two with a jumper.

Cornell's captain John Petry converted two fouls to tie the score with 1:01 left, but neither team could get the clincher, and the game went into overtime.

Kelley's jump and a driving score and foul by Deering off the pattern gave Harvard a quick five point edge in the extra session. Deering, Borchard, and Denny Lynch all scored before Cornell finally made its first points of the overtime with less than two minutes remaining. Two final baskets by Bill Baugh could only cut the Crimson's margin of victory.

Despite last night's loss to Columbia, the weekend trip must be considered a success. Coach Floyd Wilson called the team's offensive performance its best of the season, and the many easy baskets and fast breaks attest to that.

But the other features of the team's play also showed a marked improvement. When Cornell tried to crack the Crimson's shifting 2-3 zone defense by forcing it to overshift with quick passes, Harvard harried them into bad shots and then blocked out to grab the rebounds that formerly were converted into easy baskets.

With a 2-5 record the Crimson still faces a formidable task in finishing in the first division, especially since it has yet to play Princeton, which lost for the first time to Yale tonight.

But with games against Dartmouth Wednesday and Brown Saturday, the Crimson will get a chance to show its rejuvenated play is more than a passing thing.