Just inside the sold-out MGM Grand Garden on Saturday, Juan Manuel Marquez delivered a punch in the sixth round that knocked out his opponent Manny Pacquiao and made him victorious in the welterweight fight. 

The Filipino star fell face first after he missed a right punch from Marquez who used his counter right hand, landing directly on Pacquiao's chin, to close the show. Pacquiao fell in his own corner, just a foot away from ringside seaters Republican presidential candidate Mitt Romney and his wife Ann. He laid motionless for a few seconds before he was helped up to a seating position. 

Yahoo! Sports called it Marquez's "best performance in his career" and said he showed "a great deal more firepower...and seemed to be the stronger puncher" than his opponent.

"I knew Manny could knock me out at any time," Marquez said. "I threw the perfect punch. We knew he was going to come out aggressive, so we had a fight plan that was more technique and we were able to capitalize on it. "

"I got hit by a punch I didn't see," Pacquiao said.

The knockout came at 2:59 of the sixth round. Marquez also prevailed in the third round, also with his right hand, while Pacquiao put down Marquez in the fifth, according to the sports report. All three judges had it 47-46 for Pacquiao when the knockout came. Pacquiao did not appear at the post-fight news conference on Saturday, instead he was taken to the hospital for a CAT scan. 

The two boxing stars fought three matches over the a seven-year span prior to Saturday's game. What can we expect to see from Pacquiao next?

"Possible retirement, possible rematch; I'm not sure which way we're going to go right now," Trainer Freddie Roach said. "It really depends upon how he feels and what he wants to do. We'll get back in the gym and if I see signs of decline, I'll tell him to retire. If I don't, I'll tell him to go on."