Bradley Klapper

Evander Holyfield insists he has at least one more great fight left in him.

If he can summon it tonight, he will become the oldest man to regain the world heavyweight title.

Standing between the 46-year-old American and a record fifth championship is the biggest boxer to hold a major belt, Russia's gargantuan Nikolai Valuev. With his skills clearly diminished, some observers fear that Holyfield is putting his health at risk by simply getting in the ring, but the Atlanta native is confident.

"I've been boxing for 38 years and have always had to make adjustments to fight someone," said Holyfield, now over a decade removed from his two wins over Mike Tyson. "Sometimes his arms are going to be longer than yours. This time they're a lot longer."

Holyfield will also concede nearly 100 pounds (45kg) in weight to the 7ft Russian, who has lost only once in 50 career bouts and comes in as the bookmakers' overwhelming favourite.

Holyfield weighed in yesterday at a trim 214.3 pounds (97.2kg), with Valuev tipping the scale at over 310.8 pounds (141kg). The weight difference is greater than that between the standards for cruiserweight and light flyweight.

Valuev says he is not thinking about the age difference, though he adds that he watched the "legend" Holyfield a decade ago. "I don't think it is going to play a big role," he said. "We are just two boxers who will fight one another. Only that matters."

But the battle of the giant who has avoided the biggest names in the division and the aging Holyfield has generated much scepticism, some likening it to a freak show.

Holyfield has consistently downplayed his age and size disadvantages, but acknowledged that he will have to rely on mobility to neutralise Valuev's long reach and huge fists, which have knocked out 34 previous opponents.

"If he has to take one step, then I can come at him. You can't do this when your front foot is up," he said, mimicking Valuev's jab and a planned counter. That might indicate Holyfield will avoid a toe-to-toe encounter, but the fighter added: "If I catch him with a good shot and he doesn't see it coming, I know I'll knock him down."

While Valuev has great power, he has benefited from a number of close decisions in recent years and has yet to gain the recognition as champion that has been given to the Klitschko brothers, who hold the other major belts. This would be the biggest win of the 35-year-old Valuev's career.

Holyfield 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 $1m for fighting Valuev, with bigger purses waiting for unification bouts should he win, but a loss or even a draw could finally end his career. "I have to answer that question when the fight is over," he said.