GREENSBORO, N.C. — No one has ever doubted Ty Lawson's talent, speed or ability to take over a game for North Carolina. Maybe now Lawson won't hear so many questions about whether he's tough enough, too.

Lawson scored 21 of his 23 points after halftime in his return from a toe injury, and his three-point play sparked the decisive second-half run as North Carolina held off LSU, 84-70, in the South Regional yesterday.

Wayne Ellington scored 23 points to lead the Tar Heels (30-4), who ran off 11 straight points in a tie game to take control and move on to the regional semifinals in Memphis, Tenn. North Carolina will face Gonzaga, which edged Western Kentucky, 83-81.

North Carolina came into the season as everybody's pick to win the national championship. That goal would likely be over by now if not for the player coach Roy Williams has dubbed "Dennis the Menace" for his playful antics in practice.

"I've kidded the little fella, called him Dennis the Menace, and that's exactly who he is," Williams said. "But I've never seen Dennis the Menace as tough as I saw him today."

Lawson had missed the past three games after he jammed his right toe in practice two days before the regular-season finale against Duke. Williams had said Lawson had to get through practice Friday, experience no swelling later that night and get through pregame warmups to play.

Fans greeted Lawson with a loud roar that drowned out his name during starting lineups, but the speedy junior didn't look like he was at 100 percent early. He seemed hesitant when pushing the ball up the floor, and at one point in the first half came out of the game, took off his shoe and was in obvious discomfort while a trainer looked at him on the bench.

But the Atlantic Coast Conference player of the year got better as the game wore on, helping the Tar Heels rally from a five-point deficit midway through the second half to beat the eighth-seeded Tigers (27-8).

"It took me a minute to feel (the pain) out, because on defense it was hard to slide and things like that," Lawson said. "I had to figure where I could get my points at, and where I could drive and where it would feel good on my foot. It's a little sore — it's swelling up as we speak right now."

Lawson finished 7 for 13 from the floor to go with six assists and no turnovers in 31 minutes.

"Sometimes he does limp around and act soft, but I know how tough he can be," senior Danny Green said. "When the game's on the line, big-time players step up and do big-time things."

Marcus Thornton scored 25 points to lead the Tigers, who gave the Tar Heels everything they could handle even while playing in front of a hostile crowd that was at least two-thirds full of light blue. But in the end, North Carolina — a veteran team trying to return to the Final Four — had just enough to hang on.

"They didn't think they were going to lose," LSU coach Trent Johnson said of his players. "It shouldn't have ended like this. It really shouldn't have."

Tyler Hansbrough had 15 points but just one second-half field goal for North Carolina. He also needed treatment at one point for a small cut above his left eye during a scrap inside.

With the Tar Heels leading 64-63, Lawson split two defenders after a turnover and drew a foul while lobbing a shot to the rim. The ball hung there for a moment before dropping through, a three-point play that put North Carolina ahead 67-63.

After Green's 3, Lawson made another eye-popping move. This time, he lost Bo Spencer with a quick crossover dribble, drove into the paint and hit a double-pump hanging layup over the outstretched arm of 6-foot-11 Chris Johnson to push the lead to nine.

Hansbrough followed with a jumper to make it 74-63 with 4:45 left, a comfortable margin the Tar Heels didn't let get below nine the rest of the way.

"He's (Lawson) a great player, even when he's injured," Thornton said. "He's still effective because he's the head of the team. Whenever they go, he makes them go."

MORE SOUTH REGIONAL

AT THE SPRINT CENTER, KANSAS CITY, MO.

Oklahoma 73, Michigan 63: Bulling through double teams and soaring in for vicious dunks, Blake Griffin finished with 33 points and 14 rebounds to power the second-seeded Sooners (29-5) past the 10th-seeded Wolverines (21-14).

"This was so much fun," Griffin said. "This is what we play for and it's just fun when everybody is playing well and everybody is doing their thing."

Griffin finished 14 for 20 from the floor and tied Michael Beasley's Big 12 record with his 28th double-double to send Oklahoma to its deepest NCAA run since Hollis Price led the Sooners to the East Regional final in 2003.

DeShawn Sims and reserve Anthony Wright had 14 points each for Michigan, which reached the second round of the NCAA tournament for the first time since a booster scandal rocked the program in the 1990s.

AT THE ROSE GARDEN, PORTLAND, ORE.

Gonzaga 83, Western Kentucky 81: Freshman Demetri Goodson streaked the length of the court and made a short, running bank shot with 0.9 seconds left, lifting the fourth-seeded Bulldogs (28-5) over the 12th-seeded Hilltoppers (25-9).

"It's unbelievable for a freshman point guard, a big-time, big-time play," guard Micah Downs said. "He came down, read it perfectly, and then that's his shot. He practices it all the time."

Steffphon Pettigrew hit a tip-in for the Hilltoppers that tied it at 81 with 7.2 seconds left. But Goodson took the inbounds pass and went straight to the basket with little resistance, hitting from close on the left side.

"I drove left and there were two guys there, and the 'big' went with Matt (Pargo). That opened up the lane so I just took it," Goodson said. "I was really surprised to get that look."

WEST REGIONAL

AT THE SPRINT CENTER, KANSAS CITY, MO.

Memphis 89, Maryland 70: Tyreke Evans scored 19 points and the second-seeded Tigers (33-3) shot a sizzling 70 percent in the first half en route to a 53-33 lead at intermission in rolling past the 10th-seeded Terrapins (21-14) in a second-round game.

"Everybody was hitting out there," said Shawn Taggart, who had a double-double with 14 points and 11 rebounds in the start-to-finish domination of the 10th-seeded Terps. "I mean everybody. We were out there shooting the ball very well, and defense was on point today."

Greivis Vasquez, Maryland's junior guard, had insulted Memphis' much-maligned Conference USA, saying the ACC was much tougher. But with 5 minutes to go when Doneal Mack's fifth 3-pointer made it 86-57, the large contingent of Memphis fans began chanting, "A-C-C, A-C-C, A-C-C!"

Memphis' Antonio Anderson said the Tigers never paid attention to what Vasquez said.

"We're in Conference USA and love it," he said. "That's our conference, and we represent for the rest of the teams who didn't make the tournament."

AT THE ROSE GARDEN, PORTLAND, ORE.

Purdue 76, Washington 74: JaJuan Johnson scored 22 points and had two huge blocks in the final minute as the fifth-seeded Boilermakers (27-9) held off a frantic charge to beat the fourth-seeded Huskies (26-9) and advance to their first regional semifinals since 2000.

E'Twaun Moore scored 14 points and made the clinching free throws with 5.5 seconds remaining. The Boilermakers led the entire game, but nearly blew a 14-point lead to the desperate, determined Huskies.

"A lot of people talk about offensive possessions and making shots. It always comes down to making stops," Purdue coach Matt Painter said of the 6-foot-10 Johnson denying Isaiah Thomas' dash to the basket and then Quincy Pondexter's short jumper in the lane with 57.8 seconds left.

"I blocked the first shot from Thomas and I realized the shot clock was getting low. So when Pondexter got the ball, I just went after it," Johnson said.

EAST REGIONAL

AT GREENSBORO COLISEUM, GREENSBORO, N.C.

Duke 74, Texas 69: Gerald Henderson scored 24 points and hit three free throws in the final minute to help the second-seeded Blue Devils (30-6) turn back the seventh-seeded Longhorns (28-7) to reach the round of 16 for the first time since 2006.

"These last two weekends have been so gratifying to me, because it's a culmination of a lot of work and commitment," Duke coach Mike Krzyzewski said. "I've been a part of a bunch of championships — ACC, Final Fours, national championships. But to do it with this group feels great."

A.J. Abrams scored 17 points on 5-for-13 shooting for the Longhorns, who rallied from a late 10-point deficit to tie it twice in the final 2 minutes — the last time coming when Gary Johnson's free throw with 1:07 left made it 69-69.

Nolan Smith hit two free throws with 47 seconds left to put Duke up 71-69, and the Longhorns missed two chances in the final 40 seconds to tie.