It looked like it would be business as usual for Shane Carwin, the first round stoppage specialist, as he hammered mega behemoth Brock Lesnar in the first in the main event at UFC 116 at the MGM Grand in Las Vegas on Saturday night. But Lesnar hung in, stayed cool, grabbed some oxygen between rounds, and roared back in the second, for a tapout win.

UFC heavyweight champion Lesnar (age 32; Minnesota resident; 6-3; trained with Randy Couture for this scrap; 265 pounds), back after a yearlong hiatus due to a perforated intestine, came in with a 4-1 mark, while the interim champion Carwin (age 35; from Greeley, Colorado; listed at 6-2; trained by Greg Jackson; 265 pounds) was 12-0.

The two monsters talked ultra surly coming in, promising to do everything short of dismember the other. The odds in Vegas were 50-50, somewhat surprising, given that last year, you had to look long and hard for someone to fit the bill as even a credible challenger for Lesnar. But Carwin was 4-0 in UFC entering, with wins over Gabe Gonzaga and Frank Mir, both by KO-punches-1.

In the first, Lesnar, who looked MUCH thicker than Carwin up top at least, came out jabbing. But Carwin ate a few, and tasted the power. Lesnar tried to fend him off, and covered up on his back. The ref took a hard look, as Carwin rained down shots. His left eye seeped blood, but Lesnar sought to exit the round. Lesnar managed to scramble to his feet with a minute to go. He had to hope Carwin shot his wad. Both men gasped for air to the close, but Carwin looked cool as a cuke.

In round two, Lesnar got the mount, and an arm triangle. He tried to stay relaxed but couldnt break the hold, and tapped. I fell down the mountain but Ill climb back up, the loser said.

A rematch, at some point, is a given.

Chris Leben (20-6 coming in), back in action after brawling just two weeks ago (TKO-2 win over Aaron Simpson), fought Japanese star Yoshihiro Akiyama (13-1-2 entering). The Ultimate Fighter alum, who lives and fights out of Hawaii, subbed in for injured Wanderlei Silva (ribs). This was the second UFC tangle for Yoshi; he won fight of the night against Alan Belcher in July 2009. Leben did well off his back to stave off submission attempts in the first, including a tight mounted triangle, and the lefty tried to get some space, to wing his haymaker left. In the second, Leben buzzed Yoshi bad, and was then groggy himself when Yoshi landed. Leben looked boozy stumbling with 3:00 to go. Could he clear his head? He did, and tried to snap on and finish a front choke and standing guillotine. Leben landed three flush lefts, and had Yoshi in a hazy world. After the round, Yoshi couldnt even get to his stool, instead crouching and desperately sucking for wind. Leben grinned before the third kicked in. He got dropped by a right, though, with 4:00 left. He went for an armbar, impressing the judges with his effort on his back. In the waning moments, Leben pulled out a win with a triangle, forcing the loser to tap. Leben called out Wanderlei after. The end came at 4:40, via tapout, triangle choke.

CAGE DROPPINGS Ex WWE mates Steve Austin and The Rock cheered on Lesnar.