OKLAHOMA CITY ? Ivan McFarlin showed why his Oklahoma State teammates call him “The Warrior.”

With leading scorer Joey Graham seated on the bench thanks to four fouls, McFarlin powered a 10-2 run that extended Oklahoma State’s lead, and the Cowboys beat seventh-seeded Southern Illinois, 85-77, Sunday in the second round of the NCAA Tournament.

McFarlin, a 6-foot-8 forward, made 10 of his 13 shots and was 11-for-12 from the free-throw line. His 31 points are a single-game high for any player in the tournament this year. None were more impressive than the ones he scored during the decisive run.

“I was just feeling it,” said McFarlin, a fifth-year senior.

With the win, Oklahoma State advances to play in the round of 16 in consecutive seasons for the first time since 1991-92. The Cowboys (26-6) will play third-seeded Arizona next weekend in the Chicago Regional in a meeting of the two oldest coaches in the tournament. Arizona’s Lute Olson is 70, and OSU’s Eddie Sutton is 69.

McFarlin, the Cowboys’ interior workhorse, thrives in the NCAA Tournament, averaging 11.8 points and 9.5 rebounds in nine previous games.

“He comes out every night and gives it all he’s got,” teammate John Lucas III said.

In the run, McFarlin first scored on a reverse layup from a pass by Terrence Crawford, then returned the favor with a pass to set up Crawford’s right-handed jam.

After Stetson Hairston answered with a driving layup for Southern Illinois, Lucas hit a jumper in the lane before McFarlin added a pair of layups under the basket against LaMar Owen.

Oklahoma State's ivan McFarlin celebrates after a victory over Southern Illinois. McFarlin scored 31 points, and the Cowboys won, 85-77, Sunday in Oklahoma City.

The Salukis (27-8) got back within 72-68 on a three-pointer by Jamaal Tatum, but

JamesOn Curry called for the ball and answered with a three-pointer of his own. The second-seeded Cowboys hit all eight of their free throws down the stretch, and McFarlin added a two-handed jam with 44.3 seconds left to keep his team ahead.

“He just dominated us physically,” Southern Illinois coach Chris Lowery said. “It was all toughness.”

Sutton called McFarlin out of the game with 14.9 seconds left, and gave him a hug before he was allowed to sit down. Athletic director Harry Birdwell also gave McFarlin a bear hug while a crowd clad in orange stood to applaud.

Curry finished with 18 points — all in the second half — and Lucas had 17. Tatum finished with 22 points to lead the Salukis.