LOS ANGELES -- As important as physical toughness is in boxing, so too is mental strength. At the highest level, perfect focus on the fight at hand can be the difference between glory and failure.
Take, for instance, the looming showdown between welterweight titleholder Antonio Margarito and former champion Shane Mosley, who will meet before an expected sellout crowd at the Staples Center on Saturday night (HBO, 10 ET) in the first major fight of 2009.
It presents an intriguing study in fighter focus.
Both fighters are well established with long résumés of accomplishment. Margarito, 30, has won versions of the welterweight title three times, the most recent coming in July when he stopped Miguel Cotto in the 11th round of a thrilling battle that cemented his spot near the top of the sport.
Mosley, a probable Hall of Famer, has won championships in three divisions -- lightweight, welterweight and junior middleweight -- in his storied career. Even at 37, he seems to still be going strong and is coming off a highlight reel last-second 12th-round knockout of former champion Ricardo Mayorga in September.
But which one of them, Margarito or Mosley, will be the most focused on their much-anticipated bout, one that was discussed for more than a year before finally becoming reality when they agreed in November to fight?
Each certainly could have other things on his mind.
Having conquered Cotto to earn the acclaim throughout the boxing world that he has always wanted, Margarito enters the bout on a high.
Everywhere he goes, he is recognized. At boxing events, he's mobbed. He also has moved into the top 10 on most pound-for-pound lists.
"Everywhere I go now, it seems like everybody wants my autograph, everybody wants to take a picture with me," Margarito said. "I think it is more people coming up to me, and I think you can see that reflection in my popularity with the way the tickets are selling. I think without a doubt I've taken another step in my career."
In Mosley, Margarito faces an opponent who, two fights ago, lost to Cotto, the man Margarito just beat.
Is it possible that Margarito, with his newfound fame and wealth, and an opponent who lost to the guy he just beat, is looking just a little past Mosley?
After all, Top Rank promoter Bob Arum already is planning Margarito's next fight, a rematch with Cotto in June.
Margarito (37-5, 27 KOs) insists that the win against Cotto has not gone to his head and that he is not looking past Mosley (45-5, 38 KOs) to the rematch with Cotto.
"No. That will never happen to me," Margarito said. "I'm not going to say it's going to be an easy fight. He's got a lot of experience, and I'm not going to underestimate him at any time. In the ring, anything can happen, and I'm going to be ready for anything and everything.
"Obviously, between fights there have been a lot of things to do, a lot of people wanting me to do things. But I always take two months [to train] for every fight. I've always done that. I stay away from everything for those two months, and I just concentrate on fighting. That's not going to change. When it's my time to train, that's all I'm going to do, train."
Margarito didn't even want to discuss the rematch with Cotto, which Arum says will happen regardless of the outcome of Saturday's fight but as long as Cotto emerges victorious against Michael Jennings on Feb. 21.
"I'm happy that people are talking about me, about big fights, but I'm just concentrating on Mosley right now and winning this fight," Margarito said.
Sergio Diaz, who co-manages Margarito with Francisco Espinoza, said that he could understand why somebody might think Margarito was not focused solely on Mosley but that he wasn't worried.
"Not one bit," Diaz said. "Antonio does not overlook any opponents. When he was fighting on Telefutura or on HBO, no matter who he is fighting, he trains very, very hard for every single one of his opponents. After the Cotto fight, he took about two weeks off and was back in the gym. It was difficult for Antonio to get here, and he knows it will be even more difficult to stay here. That's his mentality. He wants to work even harder to stay in the position he's in, so the intensity, the sparring, the running in the mountains, was like it's always been.
"He knows you can't take someone like Shane for granted. Look what Bernard Hopkins did to Kelly Pavlik. Bernard was supposed to be this old guy, but he showed up and took him to school. If we're not careful and Shane shows up, well, I believe he has a lot left."
While Margarito has prepared under a more intense spotlight than ever before because of the rush of attention and fame after the win over Cotto, Mosley's potential distractions are far more personal.
If Mosley is distracted heading into the fight, it wouldn't be a surprise, although he insists he has blocked everything out.
He's dealing with a lot of stuff.
He remains embroiled in the BALCO scandal because of his admitted use of substances given to him by disgraced BALCO boss Victor Conte before his second win against Oscar De La Hoya in September 2003.
Publicly, Mosley has denied repeatedly that he knew the substances were undetectable designer steroids known as "the cream" and "the clear." However, in grand jury testimony recently released, Mosley admitted to injecting himself with EPO, the blood oxygen enhancer that could be the reason he was so fresh at the end of the De La Hoya rematch. The testimony also shows a Mosley who was concerned about the substances Conte had given him.
Throw in Mosley's lawsuit against Conte for defamation, and it wouldn't be a reach to suspect that maybe Mosley's mind was elsewhere.
And as a constant reminder of the legal issues brought on by his involvement in BALCO, Mosley had his attorney, Judd Burstein, sitting next to him after Thursday's final news conference, referring all questions about the situation to him.
But if only BALCO were all there is.
Mosley also enters the fight having fired his father, Jack Mosley, as his trainer and replaced him with Nazim Richardson, who also trains Hopkins.
Mosley said the change in his corner has been smooth. It's the second time he and his father have split.
"[Richardson] sees a lot of different things; he watches a lot of films, watches a lot of fighters fight, amateur and professionally," Mosley said. "So I think that kind of rejuvenated me, bringing me back to life."
And there is still more. Mosley's marriage in shambles. He and his wife, Jin, who have three children together, have been having problems for months.
Jin Mosley has managed Shane's business affairs for several years, so it was telling that she was not in attendance at the news conference.
Mosley insists none of the issues has distracted him from preparing for Margarito. He said the isolation of training camp in Big Bear, Calif., kept him away from all of it.
"I keep myself away from all the drama," he said. "I put [the problems] in the box and shut them out and that's it. I don't think about that. I'm that type of person where I don't really look at what's going on or read anything about it. When I'm focusing on boxing, it's strictly boxing. I watch fight films, I sit and stretch, everything is about the fight and I kind of put everything else aside.
"People want to bring it up, and I don't even listen. My whole thing is Margarito, I don't even care."
Jack Mosley stood off to the side during the news conference but was there show support for his son even though he has been evicted from the corner.
"I think Shane is very calm and handling things great despite what people are saying," he said. "He's a strong person. He can function under adverse conditions. What I see and hear is that he's feeling good and ready to go."
Dan Rafael is the boxing writer for ESPN.com.