Terry Holland, Virginia's basketball coach, has often said that people talk too much about how important Ralph Sampson is to his basketball team.

Tonight, to Holland's delight, Sampson gave a vivid demonstration of the fallacy of his coach's contention. The 7-foot-4 sophomore threw in 30 points, grabbed 17 rebounds, dominated the inside at both ends of the court and was clearly the difference in sixth-ranked Virginia's 91-79 victory over Duke.

Tied, 43-43, at intermission, the Cavaliers (5-0) made their first 10 shots of the second half as Sampson took over the game.

With the Cavs leading, 59-57, and Duke (3-3) refusing to quit, Sampson scored the Cavaliers' next 10 points, two on a 10-foot jump shot on which he swooped across the lane and seemed to look straight down at Duke's 6-8 center, Mike Tissaw, before shooting a line drive into the basket.

He then tipped in a Jeff Lamp miss to make it 69-61 with 10:40 left and Virginia looked ready to cruise. But with 8:44 left Sampson picked up his fourth foul and came out long enough to give Duke life. The Blue Devils got to within two, 75-73, on two free throws by Eugene Banks, but a Lamp 8-footer and a Tom Emma turnover put Virginia back in control and Duke never got within two again.

"Ralph just played great," Holland said. "He did everything we could have asked him to do. But the second half, our whole team played great."

True. The Cavaliers shot 18 of 24 from the floor the second half, Lee Raker hitting five of six to finish with 21 points. Lamp, after sitting out most of the first half because he caught a Banks elbow in the mouth and wasn't sure where he was until intermission, had only 10 points, but several came with Sampson on the bench and Duke pressing.

"The important thing was that we kept playing our game, kept taking it to them even without Ralph," Lamp said. "It's tough down here with their crowd but we did get it going well that second half."

The Cavaliers had to get it going because Duke, led by Banks' 27 points, was a tough team tonight. With no true center, the Blue Devils are going to be in trouble underneath as they were tonight, being outrebounded, 34-21. But they play a hawking man-to-man defense and don't back off.

"They're a good team," Sampson said. "They came right at me early, which is what they're supposed to do. They don't have a center, so they have to try and get the big guy out."

Duke got Sampson out for several minutes in each half, but Holland wasn't concerned because Sampson is still 11 pounds underweight after being hospitalized with a virus last month and needed to rest.

"We didn't do a bad job on Sampson," Duke Coach Mike Krzyzewski said. "I thought Tissaw battled him all night, made him get the ball outside a lot of the time. But when a kid that size makes jump shots there isn't much you can do."