Lewis probably meant Mavrovic was the toughest in terms of how much punishment he could take not in terms of how difficult a fight it was. Mavrovic was a decent euro level operator but he wasn't anything special, solid but no real weapons. His chin was top draw though, other than McCall and Mercer I haven't seen a fighter take shots off Lewis like that with so little effect.
Lewis got pretty sapped in that fight though. When you get a big man to work just above what is a comfortable tempo for him he will get that little bit more ragged with a little less pop on his punch. Remember how drained Wlad was against Brewster? He blamed it on being drugged but the truth was he was forced to exert himself that little bit more each round. Same with Lewis against Mavrovic. Pace.
While Lewis clearly never had Mavorvic subdued even when landing huge shots I think he's had tougher fights. Mavrovic didn't throw a lot in this fight only throwing 298 punches, he was persistent but other than the odd spell he rarely had Lewis in any difficulty. People perceived Lewis struggled simply because they expected him to blow the much smaller Mavrovic out. The Mercer fight was tougher. Mercer threw more, Lewis was forced to throw more and this fight was far closer on the scorecards that the Mavrovic fight. The Vitali fight was also tougher, he was behind on the scorecards was hurt by Vitali and had to alter his strategy to win the fight unlike with Mavrovic where he simply did what he always did.
Mavrovic was one of the early Euro's to turn professional in the 1990's. Since then I could probably name 15-20 better Eastern Euro's. I'm not sure he would be in the top ten for long in this decade. He might not even make it to the top ten. Mavrovic was a competent boxer, who took a good punch. Who's his best win? Maybe Julius Francis. He made his name when Lewis took him the distance. Later in the fight Marovic landed a solid right, and Lewis played it safe for the final rounds
He was a tough s****per, with a chin to be reckoned with:deal, he had LL scratching his head after their fight, Lewis probably thought the fight would be a walk in the park, but it was anything but that.. Is Zelkro still alive?? i remember about 10 years ago or so he had some serious Liver problems? He was probably on the same level as an Axel Schultz, or A Lou Savereese, a guy who isn't gonna be a top dawg, but a s****per, and a gate keeper, who can be counted on to give a good fight..
Mavrovic was a beast. He was about 30 pounds lighter than Lewis but he pushed forward and actually was the aggressor for much of their fight. Tough as nails. He gave Lewis a very hard fight. Unfortunately, Mavrovic isn't remembered or respected as he deserves to be. He gave every ounce of his heart and soul to beat Lewis but just didn't have enough to get the job done. He became very ill after the fight and lost a significant amount of weight, ending his career. One got the sense he gave EVERYTHING in the ring vs. Lewis and nothing was left in his tank. Nothing. Very underrated and under appreciated deserving WBC mandatory challenger who acquitted himself better than anyone expected vs. Prime Lewis, who at the time was being dodged by Holyfield.