Juan Manuel Lopez keeps belt with TKO

LAS VEGAS -- WBO world featherweight champion Juan Manuel Lopez defended his title by stopping Rafael Marquez on Saturday at the MGM Grand Garden Arena.

Marquez (39-6, 35 KOs), of Mexico, was unable to come out for the ninth round after unofficially losing seven of the eight rounds to Lopez (29-0, 26 KOs), of Puerto Rico, during a bout scheduled for 12 rounds.

Marquez, who had to postpone this bout once, said he wanted to fight despite a right shoulder injury he suffered before the contest. He injured that shoulder once again in the third round when Lopez responded to Marquez's aggressive entrance to the round with two strong flurry of punches. It was during one of those flurries when he injured his shoulder.

Marquez did put up a strong exchange of punches with Lopez during the fourth round, and it was the only round Marquez won. Lopez also was deducted one point for holding and hitting Marquez behind the head during the round.

Lopez was the pursuer for the majority of the fifth through eighth rounds. He was especially dominant in the seventh round, when Marquez was unable to return any of his many power punches.

Lopez backed Marquez into a corner and fired off a flurry of punches to end the eighth round. Marquez retired in his corner to referee Tony Weeks after the eighth round due to the shoulder injury and lost his first fight in his only try against Lopez.

"[The referee] asked me Are we going to have to stop this? Do you want to keep fighting?," Marquez said. "[I told Weeks] I can't go, I just can't go. "If I hadn't hurt my shoulder it would have been an all-time great fight. I'd like a rematch."

Lopez made his second defense of the featherweight title he won in January. Marquez has held the IBF bantamweight and WBC super bantamweight titles.

"He's the best fighter I ever fought," Lopez said. "If I'm No. 1, he's No. 2. He was hurting me.

"We're sportsmen. I didn't want to hurt him more than necessary. The last couple of rounds I thought I was hurting him. That's why I asked the referee to stop the fight. I didn't want anybody to get hurt.

"It's the toughest fight you'll ever see in this division. Every time he hit me he was strong as an ox."

In the main undercard fight, Glen Johnson knocked out Allan Green at 36 seconds into the eighth round of a super middleweight bout.

Johnson (51-14-2, 35 KOs) landed a left to the body and a right to the head of Green (29-3, 20 KOs) to earn the knockout. With the victory, former light heavyweight champion Johnson advances to the semifinal round of the round-robin Super Six World Boxing tournament early in 2011.

"I was fine," Green said. "He caught me in the back of the head a little bit, not purposely. I got up but the referee said it was over."

On the rest of the undercard, flyweight McWilliams Arroyo TKO'd Cesar Grajeda at 2:55 of the first round, featherweight Jesse Magdaleno stopped Matthew Salazar at 1:36 of the first round, lightweight Daniel Attah KO'd Marvin Quintero at 1:55 of the second round, welterweight Anthony Lenk won by unanimous decision over Danny Escobar, lightweight Mickey Bey was victorious by unanimous decision over Erick Cruz and super featherweight Diego Magdaleno stopped Derrick Campos at 1:15 of the fourth round.