Muhammad Ali, I guess. In all his career, he had a total of 61 fights (56 wins,37 by KO/TKO as against only 5 losses, just one by stoppage to Larry Holmes in a failed comeback at a very ripe age in 1980 ). Out of those 61 fights, 25 are world championship bouts where he won 22 of them, many by KO/TKO ). Ali turned pro in 1960 after winning the Olympic gold in Rome in the light heavyweight division and debuted by six round UD win over Tunney Hunsaker. But a year after, starting on his sixth fight he was already fighting and beating veteran campaigners and by his 15th bout, he was already fighting and beating grizzled vets and fringe contenders. After beating former light heavyweight champ and two time world heavyweight title campaigner Archie Moore by KO in his 17th fight, he would only be battling either world champions or rated contenders up to the day of his final retirement. The fighters he fought were all prominent or became prominent after he had fought them, namely: Doug Jones, Henry Cooper ( 2 fights, 2-0 ), Sonny Liston (2 fights, 2-0), Floyd Patterson ( 2 fights, 2-0), George Chuvalo ( 2 fights, 2-0 ), Brian London, Karl Mildenberger, Cleveland Williams, Ernie Terell, Zora Folley, Jerry Quarry (2 fights, 2-0 ), Oscar Bonavena, Joe Frazier (3 fights, 2-1 ), Jimmy Ellis, Buster Mathis, Jurgen Blin, Mac Foster, Alvin Blue Lewis, Bob Foster, Joe Bugner (2 fights, 2-0), Ken Norton (3 fights, 2-1 ), Rudi Lubbers, George Foreman, Chuck Wepner, Ron Lyle, Jean Pierre Coopman, Jimmy Young, Richard Dunn, Alfredo Evangelista, Ernie Shavers, Leon Spinks ( 2 fights, 1-1 ), Larry Holmes (0-1) and Trevor Berbick ( 0-1)

Many older fighters had much better resumes, simply because they had much longer careers and fought more times.

Archie Moore, Ray Robinson, Harry Greb, the list is almost endless.

Ali Bomaye...

hard question, hagler had a pretty good one probably willie pepp

Sugar Ray is greater than Zivic but Zivic unquestionably fought tougher competition.

Mayweather is greater than Oscar but Oscar unquestionably fought tougher competition.

Which boxer had the greatest competition (not necesarely wins)?