How would the 256 lb Lennox Lewis in his late 30s do against the Hasim Rahman who knocked him out in South Africa in 2001?
What about the Ray Mercer who fought Lewis in 1996? Would you make him a favourite vs. a 256 lb Lewis in 2003?
Yes. Ray Mercer fought the best fight he could that night, an overweight Lennox would have done well to push the pace to the point of winning rounds.
The Lewis who fought Vitali brought the right strategy to beat Rahman, pressuring out of a tight guard behind his jab, staying close, looking to hold+hit continously, and bombing power shots. He would have put Rahman out eventually, who was even less capable than Vitali when forced to fight at close quarters. Rahman hits harder than Vitali but I'm not sure he would be landing as much as he didn't like to throw punches when his opponent was the aggressor, Lewis would overwhelm him once again. It wasn't so much his weight or age, it is how Lewis fights. In the first Rahman fight, he didn't put enough pressure on Rahman and got knocked out while laying back; his punch out put was absurdly low in that one. Like Steward said, he told Lewis to keep throwing punches in the rematch and not let Rahman get comfortable..result was a dominating knockout.
Lewis fought out of character against Rahman in that first fight, but very much how he does in sparring for his fights. Laying on the ropes very passive. He basically treated Rahman like a second rate sparring partner and he got sparked. Once Lewis figured out how to fight, he would have never lost to Mercer again. The best version of Mercer would have still lost to 2003 Lewis. Lewis just became a different fighter back in the Garden that night and never looked back, whereas Mercer never got any better.