Iowa's Montell Marion (left) battles Air Force's Cole VonOhlen at 141. Tim Tushla photo.

OMAHA, Neb. â€" The tournament is being held in Nebraska, but the most vocal fans in the Qwest Center belong to the top-ranked Iowa Hawkeyes.

Iowa’s large black-and-gold swarm had plenty to cheer about as the Hawkeyes went 9-1 during the first session of the NCAA Championships on Thursday.

Iowa leads with 21.5 points, followed by Oklahoma State with 16. Central Michigan, Lehigh and Wisconsin share third with 15 points apiece.

The first session drew a sellout crowd of 16,358 fans.

Past national champion and Hodge Trophy winner Brent Metcalf (149 pounds) led the parade of Iowa winners in the opening round.

“It’s very premature. Nine out of 10,” Iowa coach Tom Brands said when assessing his team’s first-round showing. “You keep marching forward. The one guy has to come back and be ready tonight. We need the guys on the right side of the bracket to be ready. It's premature. You keep doing what you are about. (Ryan) Morningstar is doing what he does best, winning close matches. Anytime you put a streak together, winning nine out of 10, something is going right.”

Oklahoma State advanced seven wrestlers to the second round. The Cowboys handed Iowa its only loss of the session when unseeded Alan Gelogaev outlasted No. 9 seed Chad Beatty of Iowa 4-2 in overtime at 197.

Gelogaev escaped in the first 30-second period in the tiebreaker and then scored a takedown just before time expired. Beatty escaped midway through the second 30-second period, but could not secure a match-tying takedown.

The three-day tournament continues with the second round on Thursday night at 6:30 in Omaha. The quarterfinals and semifinals will be held on Friday with the finals set for Saturday night.

2006 NCAA champion Dustin Schlatter of Minnesota had to default his first-round match against North Carolina’s Thomas Scotton. Schlatter had injured his knee and was wrestling with a huge brace on his left leg.

Schlatter screamed in pain as he went down early in the match at 157. He was helped out of the main arena floor as fans stood and cheered. Schlatter wrestled on the U.S. World Team in freestyle in 2009.

Schlatter was a three-time All-American for the Gophers. He placed third as a sophomore and seventh as a junior.

Two big upsets â€" where Big 12 wrestlers stumbled â€"  both occurred at 165. Old Dominion’s Chris Brown upset No. 4 Jon Reader of Iowa State 5-4. Stanford’s Nick Amuchastegui defeated No. 3 seed Nick Marable of Missouri 3-1.

Amuchastegui beat Marable by the same 5-2 score in the first round of the 2009 NCAAs. Marable was a No. 5 seed last year.

Past national champions who prevailed in the first round included Metcalf, Cornell’s Troy Nickerson (125), Indiana’s Angel Escobedo (125), Michigan State’s Franklin Gomez (133), Edinboro’s Jarrod King (165), Iowa State’s Jake Varner (197) and Missouri’s Mark Ellis (285).

Past national champion Mike Pucillo of Ohio State dropped a 4-2 pigtail match to Mike Miller of Central Michigan at 184. It was the first time in the 80-year history of this event that two returning finalists met in a first-round bout.

Pucillo won a national title in 2008 and was second last year at 184. Miller was second last year at 174.