OKLAHOMA CITY - The fans in the bright orange T-shirts who packed the Ford Center for the second session of the NCAA Championships had an assortment of reasons to crank up the volume.

The arena was rocking after pins by national champs Zack Esposito, Johny Hendricks, Jake Rosholt and Steve Mocco, and a double-overtime win by Brandon Mason.

But the most thunderous round of applause was reserved for a guy wearing a Crimson singlet.

Unseeded Harvard freshman Andrew Flanagan sent shockwaves rumbling through the arena early Thursday night after stunning No. 2 seed C.P. Schlatter of Minnesota 5-3 in the second round at 157 pounds before a boisterous hometown crowd of 15,694 fans.

That win gave three-time defending national champion Oklahoma State's title hopes a substantial jolt while dealing a severe blow to top-ranked Minnesota's hopes. The Cowboys roll into Friday morning's quarterfinal round with 36.5 points and six in the championship bracket.

"Our guys are real determined, real focused," said Oklahoma State coach John Smith, whose team also has two wrestlers alive in the wrestlebacks. "We got great efforts from a lot of our guys today. Those pins are really important to help us pick up bonus points. Tomorrow is a really big day, it always is."

Sixth-ranked Oklahoma is in second place with 24.5 points, followed by a pair of surprise teams from the East Coast. Edinboro, ranked 16th, is third with 23 points and No. 19 Hofstra fourth with 19 points.

Minnesota is tied for fifth place with 22 points, but the Gophers still have four wrestlers in the quarterfinals. The semifinals are set for Friday night with the finals set for Saturday night.

The biggest shocker of the day came in the second round at 197 pounds when top-ranked Wynn Michalak of Central Michigan was upset 10-7 by unseeded Chris Weidman of Hofstra.

Flanagan held the New Jersey high school career wins record until it was broken last weekend by Mike Grey. Flanagan won the EIWA title, but was still unseeded for the NCAAs. Flanagan was 11-8 at one point this season, but hasn't lost since. He's won 16 straight matches.

"I felt real good and real relaxed going into the match," Flanagan said. "All the pressure was on him and I knew I just needed to keep the pressure on him. I knew if it was a close match and I pushed him that the Oklahoma State fans would cheer for me since I was wrestling a Minnesota kid. I really fed off the crowd and it definitely helped me."

The Flanagan-Schlatter match was scoreless through two periods as Flanagan rode Schlatter out in the second period. Flanagan escaped and then shot in for a takedown to take a 3-0 lead with 56 seconds left.

Schlatter then escaped and scored a takedown to make it 3-3 with 26 seconds left. But Flanagan had already clinched a riding-time point, so Schlatter kicked Flanagan out for an escape with just over 20 seconds left. Flanagan then held Schlatter off to win 5-3.

"I knew I could ride him," Flanagan said. "I am real comfortable wrestling in the top position and when I picked down I knew I had a chance to keep him on the mat. I want to be an All-American this year and I'm determined to do it."

Oklahoma State rebounded nicely after No. 6 seed Coleman Scott was upset at 125 in the No. 2 Cowboys' first match of the tournament. Scott bounced back with two pins in the wrestlebacks Thursday night and could still finish as high as third.

"It's never easy to come back when you have high goals and you lose early in the tournament," Smith said. "But Coleman really stepped up and came back with two pins. Those bonus points can really add up."

Two other No. 1 seeds - American's Josh Glenn (184) and Iowa State's Trent Paulson (157) - survived upset bids in the second round. Glenn outlasted unseeded Ron Howard of Cleveland State 14-10 in double-overtime while Paulson used a third-period reversal to edge unseeded Nathan Galloway of Penn State 2-0.

"I'm feeling real confident and real healthy right now," Paulson said. "The key for me is sticking to my game plan and just taking care of business. I know I can do it if I keep wrestling like I have."