Ultimate fight club: A look at the greatest bouts Picking the greatest bouts of the last 50 years is a great way to start an argument. Here is one man's top-10 list. About 150,000 spectators squeezed into Soldier Field in Chicago that night in September, 1927, and many left convinced they'd witnessed the fight of the century. The drama's high point came in Round 7 when former champion Jack Dempsey stung Gene Tunney with a savage left hook to the jaw, part of a six-punch flurry that dumped the heavyweight champ on the canvas. Tunney, his arm grabbing a ring rope, seemed glassy-eyed as he sat for 14 seconds while the referee delayed starting a count till Dempsey moved to a neutral corner. Tunney officially rose at nine, and summoning his superior boxing skills dominated the rest of the bout to keep his title. But the debate was on before the fight was over: Could Tunney have beaten the count in 10 seconds? Historians still argue about it. The transcendence of Dempsey-Tunney and the controversy over "the Long Count," as their fight is widely known, linked the legendary rivals for the rest of their days. One problem, though, in labeling any boxing match as great is that the greatness factor varies wildly, depending on how recently the fight took place, the level of passions roused by the prizefighters, and even by the number of people still alive who remember it. But flip the pages of history and many candidates for the greatest fights pop up. How about the Joe Louis-Max Schmeling heavyweight title bout at Yankee Stadium on the eve of World War II? The trio of Tony Zale-Rocky Graziano wars in the '40s? Or the Sugar Ray Robinson-Carmen Basilio middleweight title brawls in the late '50s? What about Cassius Clay-Sonny Liston in 1964? Or speed past the Muhammad Ali-era to the icons who followed him - Sugar Ray Leonard, Mike Tyson, Oscar De La Hoya, Manny Pacquiao and Floyd Mayweather Jr. Each was a publicity wizard who could draw fans, and haters, into arenas, closed-circuit theaters or living rooms with pay-per-view. On Saturday Mayweather will step into the ring for the 45th time - he's still undefeated - to face Mexico's latest star, Saul "Canelo" Alvarez. It will be great box office. Will it be a great fight? While we wait to find out, here's one boxing observer's list of, oh let's just say it - 10 great fights of the past half century. Ali-Frazier I 1971: Scene: Muhammad Ali and Joe Frazier were both undefeated heavyweight champions. Ali was banned from boxing for 3 1/2 years for refusing to join the Army during the Vietnam War. Frazier, with a devastating left hook and body punches to drain the strength out of his opponents, was the new champ. The two fought for a then-record $5-million shared purse. Madison Square Garden was stuffed with celebrities; Frank Sinatra shot photos at ringside for Life magazine. Ali's hand and foot speed had slowed during his layoff, yet he predicted Frazier would fall in the sixth. Only Frazier was laughing when that round ended. In Round 11 Frazier's left hooks wobbled Ali. He held on, then fought back. Going into the final round the referee scored it 7-6-1 in rounds for Frazier. In the 15th Frazier nailed Ali with a picture-perfect left hook to the jaw that was so hard Ali's butt hit the canvas and his legs flew up. Ali rose quickly, but the fight was Frazier's. Winner: Frazier unanimous decision 15 rounds. Ali-Foreman "The Rumble in the Jungle" 1974: Scene: Some feared the 32-year-old Ali would die in the ring. George Foreman, 25, had floored Frazier six times to win the title, then pulverized Ken Norton with three knockdowns. Ali had fought 51 tough rounds against Frazier and Norton without a single knockdown. But in Zaire, Ali tried to KO Foreman in the first round, stunning him with right-hand leads. Ali couldn't keep up the pace. So in Round 2 he improvised, backing into the ropes and against all logic invited Foreman to pummel him. "Rope-a-dope" began. In the fifth round Foreman landed a barrage of numbing body blows, but Ali countered with jolting rights that knocked the sweat off Foreman's face. After this frantic exchange Foreman resembled a huge wind-up toy that was slowing down. In Round 8 Ali's dazzling right-right-left-right-left-right combination spun Foreman to the canvas. Ten seconds, later Ali was champ again. Winner: Ali KO 8. Ali-Frazier III "The Thrilla in Manila" 1975: Scene: Ali and Frazier had fought a combined 84 bouts and both were 10 pounds heavier than in their first fight. Aging boxers with slower reflexes can't slip punches as easily. So in this fight most of the damage was delivered at close range. In the early rounds Ali stood flat-footed, for extra power, and pummeled Frazier. By the middle rounds Frazier pinned Ali on the ropes and stung him with body blows. Heat in the arena topped 100 degrees. Ali forced himself to box in the 11th round and, from longer range, his hard rights began to shut Frazier's left eye. In the 13th an Ali barrage knocked out Frazier's mouthpiece. At the end of the 14th the referee guided a bloody Frazier to his corner. Frazier could barely see, but his trainer could and he stopped it. Winner: Ali TKO 14. Leonard-Hearns I 1981: