There were two Ralph Sampsons on the court tonight for the University Virginia. The first one embarrassed himself and his team. The second redeemed both.

In the first half, the 9,000 fans in University Hall must have wondered how their school could have made such a fuss over the 7-foot-4 center. In the second half, he showed them, leading the Cavs to a 73-69 victory over Duke in a tense ACC contest.

It was the Cavs' second victroy over the Blue Devils this season, the first time they have ever performed that feat. This one was somewhat less convincing than the earlier 90-84 win at Duke, but it probably was sweeter. The Cavs ended a three-game losing streak, enhanced their chances to get back in UPI's Top 20 (they are 16th in the Associated Press poll) and broke their three-way tie with the Blue Devils and Clemson for third place in the ACC.

Duke, ranked 10th by AP and 12th by UPI, fell to 5-5 in the conference and 17-5 overall. UVA is 6-4 in conference play and 17-6 overall.

"Maybe he just needed to get tired and get back to where he belonged," Cav Coach Terry Holland said when asked to explain a game in which Sampson scored four points in the first half and 16 in the second. He was named the outstanding player of the game, although he was outscored by teammate Jeff Lamp, who had 21 and Duke center Mike Gminski, who had a game-high 24.

"He missed some shots in the first half," Holland said, "but we were getting the ball to him like we wanted to. He set up a lot of baskets for other people, so he didn't really need to score."

The Cavaliers eventually took control of the first half by unfair means. They played with five men compared to Duke's two. Center Mike Gminski with 14 points and forward Gene Banks with eight were the whole show -- discounting three travels by guard Vinne Taylor -- for the Blue Devils, while Virginia spread its scoring.

The Cavs scored eitht points in just over a minute to take a 14-8 lead and send the fans into a frenzy. Two minutes later they were quieted as two baskets by Gminski paced a return 8-0 streak by the Blue Devils.

Virginia, sparked by Jeff Jones' outside shooting, regained a one-point advantge, then suffered what appeared to be a devastating blow when freshman center Sampson was charged with his third foul.

In retrospect, it was the Cavs' biggest break of the half. Sampson's second foul had cost UVA Coach Terry Holland a two-shot technical, so he kept quiet on the third and merely sent his star to the bench. But the way Sampson had been playing, he should have sat down on his second foul. He spent most of his time practicing his outside jumper, rather than taking the ball inside. He made one of seven shots, but did make his presence felt on defense with six rebounds. Terry Gates, eight inches shorter, replaced him, undoubtedly bringing Cav fans visions of Gminski scoring at will. But Gates held him without a basket, contributing to Gminski's 2-for-11 shooting.

Meanwhile, Lamp, who had 15 points and set a school record with his 30th consecutive successful free throw, and Lee Baker combined for 14 of the Wahoos' last 16 points as they extended a 25-24 lead to as many as 12 points before going to the locker room.

The Blue Devils, who had unsuccessfully tried 1-3-1 and 2-3 zones, then man-to-man, stuck with the man-to-man early in the second half. I didn't work too well for Gminski, who allowed six quick points to an obviously aroused Sampson. His last hoop boosted the host's lead to 54-42 with 14:15 remaining.