Center Ralph Sampson keyed a 10-3 spurt at the beginning of the second half that sped No. 3 Virginia to a 74-56 victory over No. 17 Louisville in a nationally televised game today.

The Cavaliers (18-1) were leading by only three points at the half, but Sampson scored eight points and Jeff Jones made a jump shot to move out to a 48-38 advantage at 15:25 to play.

Virginia steadily increased its lead and was up, 56-44, when Sampson made an eight-foot sky hook with 7:39 remaining. Louisville managed to move within 56-50 with 5:04 left on Jerry Eaves' 16-footer following a Virginia turnover.

The Cardinals, however, went cold from the outside and were outscored, 18-6, the remainder of the way.

Sampson, a 7-foot-4 junior, finished the game with 26 points and 10 rebounds. Jones and his running mate at guard, Othell Wilson, contributed 17 points each.

Louisville (11-6) was led in scoring by Eaves with 21 points and Derek Smith with 17.

The lead changed eight times in the first half with Virginia finally going ahead for good at 24-23 on Miller's 15-footer with 8:04 left.

Although Sampson had only two blocked shots, his presence was felt by the Louisville offense. The Cardinals never were able to penetrate inside and finished the game having made only 24 of 58 field goal attempts for 41.4 percent. Virginia, with a methodical offense, sank 26 of 51 shots for 51 percent.

Louisville outrebounded Virginia, 32-31, with Scooter McCray getting 10 for the Cardinals.

Turnovers also played a crucial part in the outcome with Louisville turning the ball over eight times each half to Virginia's game-total 11.

"Ralph (Sampson) played very well in the second half, and that took us out of our momentum," said Cardinal Coach Denny Crum. "We just couldn't contain Sampson, especially in the second half. He is a very dominating type of player."

After his club had played a strong first half, Crum said, "I think we just got tired in the second half. We just ran out of gas."