MEMPHIS, Tenn. - Doneal Mack and Jeremy Hunt are more than just reserves for No. 5 Memphis. They could be the key to a long postseason run for the Tigers.

Memphis forward Joey Dorsey (32) dunks the ball in front of Marshall center Robbie Jackson, right, in the first half at the Conference USA basketball tournament in Memphis, Tenn., Thursday, March 8, 2007. (AP Photo/Mark Humphrey)

Mack and Hunt scored 19 points apiece to lead Memphis to a 92-71 victory over Marshall in the quarterfinals of the Conference USA Tournament on Thursday night.

"When they're making shots, we're really, really good, and today Doneal Mack made them, and Jeremy scored baskets, and it really busted the game open," Memphis coach John Calipari said.

Joey Dorsey added 14 points and 11 rebounds for Memphis (28-3), which recorded its 20th straight victory, the longest winning streak in the nation. Chris Douglas-Roberts scored 11 points, and Robert Dozier had 10 for Memphis.

Mark Dorris led the Thundering Herd (13-19) with 21 points, and Markel Humphrey scored 14.

Memphis, which went undefeated in conference play and is the tournament's top seed, used a 24-2 run in the first half sparked by the 3-point shooting of Mack and Hunt to build its lead to 28 before halftime.

"They're a super team and they play hard," Marshall coach Ron Jirsa said. "They forced us into turnovers early. The points off turnovers were a big key. We battled in the second half ... but we weren't able to close it to a reasonable margin."

Marshall, the tournament's No. 8 seed, opened the second half with a 13-5 run to get within 13 points, but never got closer the rest of the way.

Memphis will play in one of Friday's semifinals against the winner of the Tulsa-Tulane game late Thursday night.

Marshall advanced to Thursday's game against the Tigers by beating UAB 53-52 in Wednesday's opening round.

Mack and Hunt both got off to a strong start. Mack had 16 in the first half and Hunt 14 as the Tigers raced out to a 52-31 lead at halftime. Mack made his first six shots from the field.

Calipari said Mack's mind-set has changed since the start of the season. The freshman is going after loose balls now and taking the ball to the basket when the lane is open instead of being tentative.

"At the beginning of the season, I really wasn't doing that, and I wasn't trying to hear (Calipari)," Mack said. "Since I've been listening to him, he's been right. If I go after loose balls and be aggressive, my shot comes along."

"I knew he wasn't listening early," Calipari said laughing, "but I'm glad he confirmed it."

Tre Whitted's 3-pointer got Marshall within three with just under 10 minutes left before the break. Memphis responded with a 24-2 run that started with the Tigers hitting four consecutive 3-pointers, including three from Mack.

The Tigers led 52-24 before Marshall scored the final seven points of the half.

The Thundering Herd shot 56 percent in the first half but committed 17 turnovers, leading to 26 Memphis points. Marshall had no points off Memphis' four first-half miscues.

The Tigers pulled back their pressure defense in the second half, and the Thundering Herd finished with 22 turnovers for the game.

"You have to understand," Calipari said. "If they did not turn the ball over in the first half, it would have been a four- or five-point game. They turned it over so much. That is why we had that lead."