The victory, combined with his impressive performance in a tight loss to Miguel Cotto last year sets Mosley (45-5, 38 KOs) up for a number of big fights in the welterweight division. Mosley is hoping to get a shot at fighting Cotto-conqueror Antonio Margarito, the current poster boy at 147 pounds. Failing that, other attractive options include a rematch with Cotto and fights with Paul Williams, Joshua Clottey and perhaps unbeaten Andre Berto, who successfully defended his belt against wily veteran Steve Forbes in the opening fight on the card.
The 34-year-old Mayorga (29-7-1, 23 KOs) suffered his third loss in his last five fights, all coming against elite fighters who outclassed him - Felix Trinidad, Oscar De La Hoya and now Mosley.
Mayorga was very much in the fight through the first four or five rounds, showing better defense than he normally does and throwing more precision punches. Whether Mosley was showing his age or his strategy was to let the Nicaraguan wear himself out, the three-division champion did not look on the top of his game. Instead of using his superior boxing skills, he got into an inside fight against a naturally bigger and stronger boxer. Entering the final rounds, Mosley was obviously winning the fight, largely because he was more effective with his body punches, something he perfected in his teenage years in Los Angeles fighting a lot of classic Mexican boxers.
But Mosley had not been able to hurt Mayorga with any of his power shots until the 12th round. Then, pulling a page out of his past, Mosley pumped up the volume and relentlessly attacked Mayorga until he put him down for the first time in stunning fashion with seconds left in the fight, and then finished him off in dramatic fashion.
"Mayorga took some good shots early but I felt I could take him down later. He fought a good fight," Mosley said. "I could feel him getting weaker. I knew I had the fight won (in 12th round), but I wanted to go for the knockout because that's what the fans wanted."
In the co-feature, Berto (23-0, 19 KOs) took on his most skilled and toughest opponent to date in former world champion Forbes (33-7, 9 KOs) in his first defense of a welterweight title he won in June. Berto showed much-improved defense and tremendous conditioning, fighting as hard in the 12th round against an older opponent who has never been knocked out to earn a unanimous decision, 118-109 twice, and 116-111.
"I was cramping in the middle of the fight and I couldn't move like I wanted to," Berto said. "Steve is a slick kid. I started to dominate in the fifth and sixth rounds, and my speed won the fight. He was very elusive and durable. Now I want to take a break for the rest of the year and come back strong in 2009."
Mosley, when asked if he would fight Berto seemed to say it was not a bout he would consider now, giving the lack of drawing power of the younger fighter.