It's the ultimate boxing "What if?" question. Who would win if, in a parallel universe, Fighter A from the 1950s or '60s fought Fighter B from the 1990s or 2000s? Who would win between Joe Louis and Lennox Lewis, between Muhammad Ali and Vitali Klitschko, or between Willie Pep and Pernell Whitaker?
Today, we consider possibly the most intriguing, permanently hypothetical matchup of all. What would happen if Sugar Ray Robinson, whom most observers regard as the greatest of all time, squared off against Floyd Mayweather Jr., who considers himself to be the greatest of all time and is certainly the best boxer of his generation? Specifically, who would emerge victorious in a clash between a prime welterweight Robinson and the Mayweather who has been at 147 pounds (or higher) since 2006, recently dominated Robert Guerrero and is currently preparing to clash with Canelo Alvarez on Sept. 14?
There is, of course, no definitive determination, no right or wrong answer. But there is plenty of fodder for disagreement and discussion. Below, we provide scouting reports for both men, and our panel of ESPN.com experts picks a winner in this classic matchup.
Sugar Ray Robinson
Tall and rangy for a welterweight, he used his physical gifts to his advantage. Excellent footwork allowed him to position himself to launch two-fisted attacks from multiple angles. His stiff jab frequently morphed into a lead left hook that was delivered with exceptional torque. His overhand right, although often launched from distance, covered that distance rapidly and frequently with concussive impact. Threw blistering combinations with bad intentions and deployed a legendary repertoire of punches that he threw with almost balletic fluidity. Won his first 40 fights and lost just one of his first 123. His two-fisted power combinations enabled him to score 108 career knockouts.
Floyd Mayweather Jr.
A defensive master, he has perfected the art of the shoulder roll, which enables him to deflect opponents' blows or dodge them entirely with a subtle shift of his upper body. A study in economy of movement, he boxes with a beautiful compactness and is almost never caught off balance or out of position. Exceptionally smart in the ring, he often takes two or three rounds to assess his foe and time his punches before establishing dominance. Fast hands and feet allow him to shift into position, fire a punch and move before his opponent can respond. Skilled at luring his opponents into counterpunches. Undefeated in 44 professional outings.
Power: Mayweather can hit harder than he is often given credit for, but as a welterweight he has just two stoppages to his credit -- one of them highly controversial. Robinson had enough power to stop middleweights like Jake LaMotta, Rocky Graziano and Gene Fullmer. Advantage: Robinson
Speed: Mayweather's punches travel short distances and arrive at their destination rapidly. But in his welterweight guise, he rarely throws combinations and sits down more on his punches than he used to. Robinson delivered combinations from all angles in the form of concussive fusillades and gets the nod because of his ability to land multiple blows in short order. Advantage: Robinson
Defense: Robinson's footwork and body movement enabled him to slip punches, but often his defense was an overwhelming offense. Defensively, Mayweather might be without contemporary peer. Advantage: Mayweather
Chin: Robinson was stopped just once in his career, and that was the result of heat exhaustion in a light heavyweight bout. But he was dropped by several opponents -- mostly by middleweights but also in a challenge for the welterweight title. Mayweather has been buzzed but never decked: He touched his glove to the canvas against Zab Judah, but the knockdown wasn't called. Advantage: Mayweather
Ring IQ: Robinson fought with an intuitive rhythm and commented that, "You don't think. It's all instinct." Mayweather supplements his natural skills and work rate with a cerebral approach to his craft, studying his opponents in the ring and making adjustments on the fly to neutralize their strengths. Advantage: Mayweather
Dan Rafael: Robinson knockout
Floyd Mayweather Jr. is great, but Sugar Ray Robinson is the greatest ever and would beat Mayweather if we could somehow make the fight happen. Robinson wasn't as fast as Mayweather and didn't have his kind of defense, but he was the total package. He could take a shot and he had power in both hands, while Mayweather isn't a big puncher with either hand. He would easily match Mayweather skillwise. Remember, Robinson was undefeated as an amateur, and, at one point as a pro, he was 128-4 and had a 91-fight unbeaten stretch.
Plus, he didn't cherry-pick opponents. He fought the best of the best when they were on top of their games, unlike Mayweather, who has mostly feasted on older or smaller guys since he became a welterweight. The supremely talented Robinson would press forward and make Mayweather's night hell. Eventually, he would put together his combinations, stiffen Mayweather's legs and get him out of there in about 10 rounds.
Teddy Atlas: Robinson decision
Robinson was a bigger man and, in my estimation, the greatest welterweight of all time. Mayweather is a fine fighter, but he's not quite in that rarefied air, and his experience pales in comparison. You talk about the speed of Floyd, but Robinson could meet that speed -- and Mayweather isn't as consistent a combination puncher. Sure, Robinson wasn't the hardest guy in the world to hit, but he had one of the greatest chins of all time. Floyd is a better defensive fighter, and he would have to use his legs more than he does now to keep Robinson off balance. But, at the end of the day, Robinson is too strong, consistent and steady.
The adjustment Robinson would have to make is to go to the body, and I see him controlling the action with his jab in the center of the ring and stabilizing Floyd, who would have a long night. I like Robinson to win, and I think he would have a chance to stop Mayweather late.
Kieran Mulvaney: Robinson decision
We can only infer how good Ray Robinson was as a welterweight, because of the lack of tape of him at 147 pounds. But to watch footage of some of his middleweight contests is to marvel at the fluid combinations, violently torqued punches and effortless footwork he was still exhibiting even when he was past his peak. One thing that's evident is how well Robinson matches up physically with these nominally bigger men; he would have had sizable physical advantages against Mayweather, and he would have used them effectively.
I picture Robinson launching violent left hooks and overhand rights in constant combination, throwing punches from all angles from distance and forcing Mayweather to cover up. Mayweather's defense would have enabled him to slip some of those blows and survive the barrage, but he would be stuck in defensive mode all night, never able to launch any offense beyond occasional scoring counter right hands. I see a wide unanimous decision for Robinson.
Nigel Collins: Robinson decision
Sugar Ray Robinson was everything that Floyd Mayweather Jr. is, and much more. But that doesn't mean this fight would be a walkover. "Money" is a marvelous fighter who has the skills to give any welterweight in history an uncomfortable night.
I see the bout unfolding along the lines of Robinson's 1946 match with Tommy Bell for the vacant welterweight title. Bell was a skillful boxer with a good punch, and Robinson had to come off the deck to win a competitive but unanimous 15-round decision. I don't see Mayweather knocking down Ray, but he'd land enough to make it interesting.
Robinson's chief advantages would be his punching power and aggression. You have to take a risk to land a big punch, and putting himself anywhere near harm's way is usually the last thing on Mayweather's mind. Sugar Ray, on the other hand, was always willing to go after the other guy. Call it Robinson via unanimous decision.
Eric Raskin: Robinson decision
This is frankly unfair to Floyd, to pair him against the most perfect fighter who ever lived. When you look at the 147-pound version of Robinson, you're looking at a fighter who could do everything Mayweather does just as well as Mayweather does it -- but who also had elite punching power. Additionally, Robinson's opposition over the course of his career allowed him to build up a bank of experience that would serve him well in any difficult moments against Mayweather. For Mayweather, on the other hand, although it's a testament to his magnificent skill that he remains somewhat untested after 44 pro fights, against Robinson he would find himself dealing with adversity he has never dealt with before.
In the end, the greatest sign of respect I can show Mayweather is to predict that he lasts the distance -- something not many opponents did against a prime, welterweight Robinson. Both guys make brilliant adjustments throughout the fight, but Sugar Ray is generally a half-step ahead and doing much more damage with his punches en route to a decisive points win.
Michael Woods: Draw
My respect for Floyd Mayweather's talent has grown in the past several years. I see no one from 140 pounds up to 160 taking his "0" from him. But the original Sugar Ray comes from a different time, when boxers fought with insane frequency, and I think his talent and the intangibles he'd bring to the table would give him a better chance at besmirching Floyd's record than any man campaigning today.
For the sake of brevity, shall we put the SRR who beat Jake LaMotta in their second fight, on Feb. 26, 1943 -- three weeks after their first tangle -- in against Floyd in our mythical matchup? That Robinson was 40-0 and outweighed LaMotta by 16 pounds. But he got the unanimous decision in 10 rounds, and maybe he'd get the decision against Floyd … but maybe not. I'm not sure how it would play out stylistically. Who would be the aggressor? One tangible edge I see Robinson having: His power would bother Floyd more than Floyd's would bother Robinson. Then again, I think Floyd's athleticism and effectiveness slipping punches would make him hard to handle for Sugar. Verdict? A draw. And by all means, let's book the rematch while we bust on Woods for fence-sitting.
Brian Campbell: Robinson knockout
Mayweather has established himself as a historically great defensive fighter and elite counterpuncher. But there's a reason Robinson, who at his peak carried a gaudy record of 128-1-2 with 84 KOs, is considered the best of the best. He had the total package of speed, size, defense and technique. But what would have separated him from Mayweather was his power. Bert Sugar once said Robinson could "deliver a knockout blow while moving backward." And although I'm not implying that Robinson stops Mayweather with one punch, as Floyd's chin is his most underrated strength, I believe Robinson would have caught up to "Money" with the frightening combinations that became his calling card.
With Mayweather's exceptional ring IQ and ability to adjust to any style, it has been nearly impossible for anyone to hurt him late in fights. That's why Robinson would have to do damage early, when Mayweather has shown vulnerability, en route to a fourth-round TKO.
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