CLEMSON, S.C. - Kyle Parker didn't get angry or pout when he was sent to the bench for the two most important games of Clemson's season.

Mired in a slump, the former cleanup hitter, tried to stay focused and prepared.

"I told myself, 'Whatever opportunity I got, I'm going to try to capitalize on it,'" said the sophomore outfielder, one of two contenders to be the Tiger football team's starting quarterback this fall.

Parker did make the most of his chances, lacing a two-run single into left field in the eighth inning to lift the Tigers to a 6-5 victory over Oklahoma State in the deciding game of the Clemson Regional.

The Tigers (44-20) will play at Arizona State this weekend in the SuperRegionals. The Cowboys (34-24) had to be content with silencing critics that said they didn't belong in the 64-team NCAA field after finishing ninth in the Big 12 Conference regular season.

Senior Matt Vaughn (4-1) pitched the final 3 2/3 innings for the Tigers, who rallied from a 5-1 deficit going into the bottom of the seventh.

Parker, a starter all season until Sunday night's first game against Oklahoma State, was the first hitter faced by OSU closer Randy McCurry, who replaced tiring starter Tyler Lyons (7-6). Parker had come into the game as a pinch-hitter the previous inning and popped out.

But he drilled a high curveball from McCurry, allowing Ben Paulsen and John Nester to score.

"I knew I wasn't performing as well as we needed," Parker said. "It's kind of been biting at me not the clutch hit. I just recognized the curveball and was able to put a good swing on it."

Lyons, who had thrown 5 2/3 innings in Friday's regional opener, was in command for the first six innings.

Clemson, which scored all six of its runs with two outs, started its comeback with the help of an error in the seventh. Chris Epps followed with a two-run homer that cut the margin to 5-3. The Tigers added another run in the inning on Jeff Schaus' single.

With two outs in the eighth, Nester doubled into the gap in left-center, putting runner on second and third. The Cowboys brought in McCurry, a freshman right-hander, setting up Parker's game-winning hit.

Mark Ginther homered for the Cowboys. Tom Belza, who hit four homers in OSU's first two tournament games, had two RBIs.

Lyons, who threw 107 pitches Friday, threw 111 pitches Monday.

"On two days rest, that might be as good a performance as we've had this season," Oklahoma State coach Frank Anderson said. "He's the toughest kid we've got on this team."