ZURICH, Switzerland — Evander Holyfield has had his share of doubters over the years, from experts who saw him as little more than a beefed-up cruiserweight to others that said he lacked the power to be heavyweight champion.

Now aiming to win the heavyweight title a record fifth time, the 46-year-old fighter says he has no patience for those who think he's too old or fear he's putting his health at risk.

"They've been calling me old since I was 30 years old," Holyfield said. "When you come up poor, everyone is always doubting you. Someone always tells you that you can't do something. I never listened then, so why in the world would I get into that thinking now?"

In an interview with The Associated Press on Monday, the fighter from the Atlanta area acknowledged that he had little time left in a three-decade career that saw him rise from undefeated cruiserweight to conqueror of heavyweight champions including Riddick Bowe, George Foreman and Mike Tyson.

But he still wants to end his career on top, and to do that says he has to reunite the division's top belts as its undisputed champion. The improbable comeback quest begins Saturday night in Zurich with a tall challenge — literally — in Nikolay Valuev, the 7-foot, 300-something-pound Russian who holds the WBA belt.

"This is not to prove anything to anyone," said Holyfield, who rejects that his latest comeback is linked in any way to recent financial troubles. "I box because I'm skillful and I'm good, and I love what I do. It's not because I'm angry, or because I'm mad. You jump in the game so that you can be the best."

Holyfield hasn't fought since losing a one-sided decision to then-WBO champion Sultan Ibragimov more than a year ago. He is winless in his last four title fights since beating John Ruiz for the vacant WBA belt in October 2000, but says his movement, balance and reflexes are back to their best levels in eight years.

Holyfield, who had his license to box in New York state revoked three years ago, underwent five hours of medical tests in Germany last month to show he was fit to fight. He is expected to earn between $750,000 and $1 million for fighting Valuev, with bigger purses waiting for unification bouts.

The fight bears an eerie resemblance to a Hollywood plot, with an aging American legend meeting a Russian giant largely unknown to U.S. boxing fans. Holyfield showed no fear of life imitating art, or in this case Sylvester Stallone's "Rocky IV" and the scene when character Apollo Creed dies in the ring.

"When I was young, they said 'Mike Tyson is going to kill that boy,'" said Holyfield, who beat Tyson once by technical knockout and again when Tyson was infamously disqualified for biting Holyfield's ears.

"They said I couldn't handle Michael Moorer's left hook," he added, referring to his 1998 victory, avenging a loss four years earlier. "I knocked him down five times."

Holyfield said he will try to keep moving to prevent Valuev from planting his front foot and controlling the fight with his long arms. Standing in his hotel room and shadowboxing the air, he said constant lateral movement would force the big Russian to either shift weight onto the back foot or move in with his head while punching — leaving him vulnerable in either case.

"If he has to take one step, then I can come at him," he said, mimicking Valuev's jab and a planned counter. "You can't do this when your front foot is up. When you adjust your feet, that's when I come in."

Holyfield, whose career record stands at 42-9-2, refused to say if he would keep fighting or retire should he lose or only draw. But he said he was more prepared now to hang up his gloves, insisting that he was well set up financially for life after boxing.

The fighter agreed in October to give his 10-year-old son a $100,000 college fund while facing the threat of possible jail time and an auction on his home. Last summer, he failed to make three straight $3,000 monthly child-support payments.

Holyfield blamed his problems on people who took advantage of him while he was concentrating solely on boxing. He speaks now of vague plans to build a "brand Holyfield" that his children will carry on, but does not mention any specifics of the business he will enter after retirement.

"I am still a young man," he said. "I can't go back and start going to clubs. I don't want to train boxers and have to be a daddy for grown men, wiping their noses. I got my own kids to raise. And I'm not going to be in a smoky place signing autographs for a living."

In boxing as in life, he said, you can make mistakes when you are young because the recovery is so much quicker. "With age, it has to be precise," he added. "I used to get off plan all the time. When you're older you can't do that."

Holyfield spoke nostalgically of his old fights, from his early heavyweight encounters with James Tillis and Michael Dokes to three epic battles in the 1990s with Riddick Bowe, two of which he lost. He declined to speculate on a possible big payday rematch with the 41-year-old Bowe, who scored a comeback win on points over Germany's Gene Pukall this weekend in the undercard of Wladimir Klitschko's latest IBF heavyweight title defense.

Holyfield was less gracious, however, when it came to Lennox Lewis. The pair fought twice, with the first ending in a draw and Lewis winning the second convincingly by scorecard. Holyfield insists he beat Lewis, though few who watched either fight would agree.

Still, he said he holds no grudges.

"You're only as good as the people you've fought," Holyfield said. "And I've fought them all."