For Pacquiao, will the beat go on?

Plenty of top boxers get brutally knocked out at some point in their career. But how many all-time greats recover from a big knockout and return to their once-lofty perch? It's uncommon.

Roberto Duran had some big wins after being flattened by Thomas Hearns via a brutal second-round knockout in 1984. Lennox Lewis rebounded from a crushing fifth-round knockout against Hasim Rahman to drill him in the rematch in 2001 and regain the heavyweight championship. Lewis then finished his career with two more big wins, stopping Mike Tyson and Vitali Klitschko.

Wladimir Klitschko, Vitali's younger brother, also recovered extremely well after suffering two knockout losses in a four-fight span in 2003 and 2004. After his knockouts to Lamon Brewster and Corrie Sanders, many thought Wladimir was finished. But the joke was on us, because not only did he recover, but he went on to fashion one of the great heavyweight championship reigns in boxing history.

Wladimir has been untouchable since 2005. He won a world title in 2006, has since added various belts to his collection and has made 15 defenses, third-most in heavyweight history.

The more common situation, however, is that when a once-great fighter gets knocked out, he struggles to come close to his past greatness. Roy Jones Jr. is one prime example. He won world titles in four divisions from middleweight to heavyweight and spent the better part of 10 years -- 1994 to 2004 -- as the No. 1 pound-for-pound fighter in the world.

But after Antonio Tarver knocked him silly in the second round of their 2004 light heavyweight championship rematch, Jones was never the same.

So with an eye toward history, this inevitable question comes: On which side will Manny Pacquiao land?

The all-time great Filipino icon has won world titles in a record eight weight classes, earned fighter-of-the-year honors three times, and was named fighter of the decade for the 2000s.

But after being knocked cold by one punch last December by his great rival, Juan Manuel Marquez, many wonder if Pacquiao will ever be the same.

After nearly a year off, he will return to face Brandon Rios on Saturday (9 p.m. ET, HBO PPV) in Macau, with many wondering if PacMan will be able to recapture past glory.

I asked Wladimir Klitschko and Jones about their experiences trying to recover from significant knockout losses. The common theme from both was that they questioned themselves: Why did the knockout happen? What could have been done differently than before?

"I can't really tell you why I did it in the way I did it," Klitschko said of his rebound after losing to Brewster via a fifth-round knockout in 2004. "After the Lamon Brewster fight, even my brother asked me to retire. But my gut feeling and my common sense told me that I can do it better than I did, and I dedicated myself 100 percent to payback for all the criticism I received in those times, and I'm still not done with that yet even if I got all of my titles back.

"I guess it's all about to satisfy my own ego, which is big. I love it this way, though. I guess this feeling is in a certain way addicting, too.

"After the Brewster fight, I went on the floor of the sport. I was a loser from the two of the brothers. It was embarrassing to me. From that time on, I fell in love with boxing because I knew it was my last chance. Also, I would never love the sport as I do now if there was no Emanuel Steward [Klitschko's late trainer and friend] by my side. He made me fall in love with [boxing], big-time."

While Klitschko's career has been dominant since the knockout losses, Jones' has been the opposite as he hangs on and continues to fight sporadically at age 44. The first loss to Tarver was the first of three in a row for Jones, followed by another big knockout loss to Glen Johnson and a one-sided decision loss to Tarver in their rubber match.

Jones has mixed in some success, but he hasn't been a serious title contender since the three-fight losing streak. Since being knocked out by Johnson, Jones has also suffered two other knockouts: a first-round knockout to Danny Green and a truly frightening 10th-round obliteration by Denis Lebedev in a 2011 cruiserweight fight. Jones has won two fights in a row since, but with mediocre performances against lesser opponents.

"It's a very tough thing to come back from a KO like that [against Tarver]," Jones said. "You have to look at yourself and ask if I am the same fighter and 'why did that happen?' Once you ask yourself those questions, you can be strong. It takes a very strong-minded person to not have it happen again. Usually when it happens, you never saw the punch coming. If it happens too many times, maybe it's time to stop. We always know getting knocked out is a possibility. Manny knows that."

Jones said it took him a while to recover from the back-to-back knockouts at the hands of Tarver and Johnson. He attributed it to the fact that he lost about 25 pounds to face Tarver after he had outpointed John Ruiz to win a heavyweight title.

"My problem was the weight," Jones said. "With Manny, he had been in the ring with Marquez for three previous fights, 36 rounds. Marquez knew a lot about him.

"I want to see how Manny takes the first clean punch landed by Rios, and then I'll know how he is. Even Pacquiao doesn't know how he is right now or how he will react to that first big punch. But Manny did the right thing. He took almost a year off. He isn't suffering from a weight-loss situation. He got caught with a shot by a guy who he had already fought three times. But he gave his body a chance to rest and it was the smartest thing he could have done."

We might find out for sure if that was the case come Saturday night.