Vitali Klitschko has had an accomplished career. The big Ukrainian has won major heavyweight titles three times. He has had a long career, beginning in 1996, going on hiatus for almost four years and then returning last year. And he has won consistently; he’s 36-2, with an eye-popping 35 knockouts.

However, Klitschko, who faces Juan Carlos Gomez on Saturday, might be defined by two events: a loss to Lennox Lewis in which he won the respect of the boxing world and his remarkable comeback after the long layoff.

To understand the significance of the Lewis fight, in 2003, we should go back to his meeting with Chris Byrd in 2000. Klitschko, outboxing the much-smaller man, was winning a one-sided fight when he retired with what was later determined to be a torn rotator cuff.

After surgery to repair the damage, Klitschko came back to win his next five fights – four by knockout – to set up the showdown with Lewis in Los Angeles.

Still, going into that fight, many boxing observers questioned Klitschko’s heart because of his decision to retire against Byrd and the fact he was seen more as a tactician who uses his height and reach to keep opponents at bay than real fighter.

Meanwhile, Lewis was 37 at the time, and perhaps not in the best of shape, but he was coming off his spectacular knockout of Mike Tyson almost exactly a year earlier and was considered a heavy favorite over the plodding Eastern European.

Once the opening bell rang, a lot of people were surprised. Klitschko didn’t back down in spite of a horrible cut above his left eye, the result of a punch in the third round. He matched Lewis hard punch for hard punch and was leading by two points on all cards when the fight was stopped after the sixth round.

Klitschko lost the fight – his second and final setback – but proved to be a warrior at least on that night.

“He learned from the Byrd fight,” said Teddy Atlas, trainer and television analyst. “He learned what happens when you stop behaving like a fighter, when you pull yourself out of a fight. He found out what goes with that, how difficult those things are to live with.

“Against Lewis he acted like a guy who found that out. He wasn’t going to take himself out of a fight a second time no matter how severe the cut was. The (officials) did what they had to do, pulling him out, but he was going to fight on.”

Unfortunately for Klitschko, the physical problems didn’t end with the shoulder and the cut.

He pulled out of four consecutive fights because of injuries – three scheduled bouts in 2004 against Hasim Rahman, the last of which prompted his retirement – and a comeback bout against Jameel McCline in 2005. His body just wouldn’t cooperate.

As he put it in a statement released at the time, “”Unfortunately, I've been fighting injuries recently more than facing rivals in the ring.”

However, after giving his body time to heal and then working out with brother Wladimir, Vitali began to feel as if he could giving boxing one more try. One thing led to another and he ended up in the ring against fierce Samuel Peter last October – 3 years and 10 months after his most-recent fight.

That’s a long layoff, particularly for a 37-year-old with a brittle body. And he didn’t exactly ease back into boxing: Aside from Wladimir Klitschko, Peter was probably the most-feared heavyweight in the world because of his power and aggression.

Peter had put younger Klitschko brother down three times before losing a unanimous decision in 2005, convincing evidence that he was no pushover.

In the end, though, everything went Vitali Klitschko’s way. Appearing to be as fresh and sharp as any active fighter, he used that height, reach and determination to pick Peter apart and ultimately make him quit on his stool after the eighth round.

Peter didn’t’ seem to be Peter. He didn’t have the fire he’d shown in the past; it was almost as if he didn’t show up. However, Klitschko must be given credit for an exceptional performance under the unusual circumstances.

It was one of the most-impressive comebacks in memory.

“For Vitali to come out of a four-year retirement and make one of the top heavyweights, Samuel Peter, quit, is pretty good work,” said television analyst Larry Merchant.

Pretty good, indeed. In one night, Klitschko went from retired underachiever to world titleholder for a third time. Many experts feel he’s the best heavyweight in the world , even better than his younger brother.

Not bad for a guy who lost his biggest fight and had to retire because of chronic injuries.

Michael Rosenthal can be reached at [email protected]