Sitting stone-faced on the bench for the entire game, Maryland women's basketball Coach Chris Weller's expression finally cracked with five seconds remaining.

A smile emerged, as did the Terrapins today in surprising North Carolina State, 77-55, in the first round of the Atlantic Coast Conference tournament before 1,574 at the Cumberland County Arena.

Maryland, which had lost to the Wolfpack by an average of 20 points in two regular-season games, saved its best effort for today. It was the quickest exit for defending champion North Carolina State (18-10), which had made the final seven times in the eight-year history of the tournament.

The win allows the Terrapins (15-12) to advance to play Virginia (26-1) Sunday at 4 in the semifinals. Virginia, the nation's third-ranked team, defeated Georgia Tech, 90-64.

In the other semifinal, North Carolina, an 88-83 winner over Clemson, will meet Wake Forest, which beat Duke, 72-71, for its first-ever ACC tournament victory.

"This is our best effort by far," said Weller. "We played a great half of basketball and then the bottom fell out for them."

The Terrapins made their move midway through the first half with aggressive defense. The Wolfpack shot only 34 percent in the first half and 37 for the game. Maryland led at the half, 35-24.

In the second half, Wolfpack center Trena Trice, a first-team all-ACC pick who had 19 points and 18 rebounds the last time the two teams met, watched from the bench with four fouls as Maryland dominated inside. She finished with 17 points and eight rebounds.

"We made a couple of mistakes early and it slowed us down," said North Carolina State Coach Kay Yow. "We got tentative. It was our worst game of the whole season. It's the most disappointing loss, no doubt about it. It's one of those games I can't find anything good."

Senior Chequita Wood, who got most of her points inside, led Maryland with 19 points and 11 rebounds. Point guard Deana Tate had 18 points, Lisa Brown 17 and Carolin Dehn-Duhr 13.

Brown was primarily responsible for giving Maryland its 11-point halftime lead, scoring 16 points and coming up with important steals. With the Terrapins leading, 11-10, she put in two 15-footers to help Maryland to a 19-12 advantage.

After N.C. State called a timeout with 8:37 remaining, Brown stole the ball and passed to Tate for a layup for a 21-12 Maryland lead. The closest the Wolfpack got thereafter was six points, 24-18, on Trice's inside basket.

"We tried to penetrate our guards and play the way they did against us the first two times," Weller said. "We wanted to be the aggressor in this game. When we were so aggressive with our defense, it spilled over into our offense."

In the Virginia-Georgia Tech game, the Cavaliers broke it open in the final minutes of the first half. After Ida Neal brought the Yellow Jackets to within 22-20 with a free throw, Trina Thomas scored on a baseline drive and guard Donna Holt scored eight straight points to help the Cavaliers to a 42-26 halftime lead.

Holt led Virginia with 23 points. Nancy Mayer and Daphne Hawkins, the team's leading scorer who had missed the previous five games with a sprained knee, each had 14 points. Thomas had 11 rebounds.

For Georgia Tech (10-17), sophomore forward Marielle Walker had 27 points and 6-foot-7 center Dolores Bootz had 19. Colonial Athletic Association Tournament

In Wilmington, N.C., Sylvia Bragg's two foul shots with three seconds left gave East Carolina a 69-68 semifinal win over American.

American (20-7) had taken a 68-67 lead with nine seconds left when Dana Diller hit a jump shot from the right wing. ECU (23-6) called time with eight seconds left, then Bragg was fouled going down court.

East Carolina plays James Madison for the championship today.