North Carolina's Dean Smith, who has won more NCAA tournament games than any active coach, will have another chance at winning the national championship that has eluded him for 20 years. He got that opportunity today when his Tar Heels defeated Houston, 68-63, at the Superdome.

Smith will try for his first victory in four trips to the final on Monday night, when North Carolina plays Georgetown, a 50-46 winner over Louisville in today's second game. Tipoff is scheduled for 8:12 EST.

In all those years, Smith has never had on one team two such agile, talented and experienced giants as James Worthy and Sam Perkins--a pair of all-Americas who demonstrated again today just how thoroughly they can dominate the nation's best teams.

North Carolina defeated Houston principally because the Cougars didn't have a clue about how to stop Perkins and Worthy. Another reason the Tar Heels won is that they held guard Rob Williams--Houston's leading scorer, averaging almost 22 points per game--without a field goal.

Top-ranked North Carolina (31-2) has won 15 straight games, the nation's longest winning streak. It is the first team to play in two consecutive championship games since the UCLA teams of 1972 and '73, which were led by Bill Walton and won each year. North Carolina lost to Indiana last year.

"It would be nice to go away by winning one, so you guys wouldn't have to ask me all those tough questions," said Smith, jubilant. He is 23-13 in NCAA tournament play, but failed to win the championship in six previous trips to the final four.

If Worthy and Perkins play as well as they did today, it will be very difficult to keep Smith from obtaining the title that has escaped him.

Perkins, a 6-foot-9 sophomore center, scored 25 points, making nine of 11 shots, and had 10 rebounds. Both were game highs. Worthy made seven of 10 shots--including two slam dunks that mesmerized the record crowd of 61,612 and broke a spirited Houston comeback.

"Worthy is just great, so is Perkins," said Houston forward Clyde Drexler. "They just took it to us, and we weren't expecting some of the moves they made."

Even with Perkins and Worthy playing so convincingly inside, the Cougars came back from a 14-0 deficit in the first five minutes to tie before halftime.

But Williams missed eight field goal attempts and scored just two free throws. "This has never happened to me before," he said. "I can't believe it. I feel pretty bad right now."

Houston (25-8) got 20 points from guard Lynden Rose, 18 from center Larry Micheaux and 17 from Drexler. But the Cougars missed their first seven attempts, and shot only 36 percent in the second half. The Tar Heels made 76 percent (13 of 17) after intermission.

"I don't believe there's ever been a shutout in the final four," said Houston Coach Guy Lewis, "but there certainly looked like there would be one today. I didn't think we would ever score. The start of the game just killed us."

The Cougars didn't score until Drexler's base-line jumper made it 14-2, with 5:05 gone in the game. But Houston, with good offensive rebounding, pulled itself together and tied at 29 on Micheaux's inside basket with 1:45 left in the half.

"I thought we were in great shape at the end of the first half," Lewis said, "because we didn't play worth a darn and still only trailed by two."

But Houston had trouble at the start of the second half also, allowing North Carolina to score seven of the first nine points for a 38-31 lead. Houston pulled to within four points several times late in the game.

But once North Carolina went to its delay game, with 7:05 remaining, the Tar Heels made 10 of 11 foul shots to secure the victory.

Many Houston fans must have left this game thinking, "What if Rob Williams had scored just half of his season average?"

North Carolina guard Michael Jordan said, "If somebody had told me before the game that Rob Williams wouldn't have scored at least one field goal, I just wouldn't have believed it."

Williams, a junior who talked earlier this week of passing up his senior year to turn professional, looked jittery at the beginning. He shot one air ball, and banged two shots off the side of the rim on straight-ahead jumpers.

"We depend on Rob for at least four or five baskets," Micheaux said. "I was expecting this to be his best game ever. I kept thinking he'd break out of it by hitting one."

"Williams is a much better player than he showed today," Lewis said. "It just didn't look like he was trying hard enough to score."

Williams was in a fog 30 minutes after the game, still searching for the reasons for his poor performance.

"My shot wasn't falling from the beginning," Williams said, "so I decided not to hurt the team anymore by shooting. I decided to help them in other ways."

North Carolina's Jimmy Black, who guarded Williams when the Tar Heels played man-to-man defense, said he understood how a prolific shooter could have such an off night. "It's hard to shoot in here," Black said. "The background seems like everybody is on the outskirts of town."