With Berto, Floyd Mayweather has a chance at a rare happy ending

He insists this is his last fight. Many anticipate that it’s not.

But one thing’s for certain: If Floyd Mayweather Jr. is indeed planning to end it all following Saturday night’s go-round with Andre Berto at the MGM Grand in Las Vegas, he’s got a good chance to go out on a higher note than many other greats have.

Unlike the John Elways, Joe DiMaggios and Bill Russells of the world, boxers are a group that tends to stick around too long, riding out the slow, often painful decline from marquee world champion to the punchy also-ran.

Here’s a look at a handful of all-timers whose finales weren’t as grand as intended.

Muhammad Ali

Date: Dec. 11, 1981

Site: Nassau, Bahamas

Result: L (UD 10) Trevor Berbick

The sound of a cowbell rang out to start and end rounds, which is perhaps the most lasting memory of “The Greatest’s” Caribbean end.

Fourteen months after being pummeled into his first career stoppage loss by Larry Holmes, a nearly 40-year-old Ali insisted he’d turn back the clock against a burly Jamaican-turned-Canadian who himself had lost to Holmes eight months earlier.

Instead, Ali weighed a career-high 236 pounds and was never able to resemble a shadow of himself, let alone a foe with a real chance to defeat a 27-year-old opponent. He dropped a unanimous decision and finally conceded reality after the final bell.

"Father Time caught up with me. In my younger days, I wouldn't have had any trouble. But I just couldn't do what I wanted to do,” he said. "It's not [that my skills] may have gone. They have gone."

Oscar De La Hoya

Date: Dec. 6, 2008

Site: Las Vegas, Nevada

Result: L (TKO 9) Manny Pacquiao

Going in, no one would have expected an end to the “Golden Boy.” In fact, the idea of matching a former 154-pound champion with a fighter who’d begun his career at 106 pounds seemed ludicrous in De La Hoya’s favor -- even at a 147-pound catch weight.

But it didn’t quite work out that way.

Pacquiao dominated from the opening bell with hand speed, foot movement and blistering combinations, while a flummoxed De La Hoya was unable to pull the trigger on punches in the few moments where his man was within striking distance. The beating grew worse and the rounds elapsed, ultimately leaving De La Hoya to surrender on his stool after Round 8.

"We knew we had him after the first round. He had no legs, he was hesitant and he was shot," said Pacquiao trainer Freddie Roach, who’d insisted going in that De La Hoya was past his best. The beaten man met Roach in the ring afterward and conceded, saying "You're right Freddie. I don't have it anymore." Afterward, De La Hoya hinted at his ultimate decision. "My heart still wants to fight, that's for sure,” he said. “But when your physical doesn't respond, what can you do? I have to be smart and make sure I think about my future plans."

Joe Frazier

Date: Dec. 3, 1981

Site: Chicago, Illinois

Result: (D 10) Floyd Cummings

Just eight days before his long-time rival, Ali, was scheduled to return in the Bahamas, a stubborn “Smokin’ Joe” made his first appearance since being freight-trained for a second time by George Foreman more than five years earlier.

But, like Ali’s, his return wasn’t a good idea.

A 229-pound Frazier reached the ring with a roll of fat around his belly, though his unheralded foe -- even at 15-1 with 13 knockouts in the record book -- was unable to do the sort of one-sided number on him that Berbick was ultimately able to do on Ali in the Bahamas.

All three ringside judges scored it even, and Frazier called it a career. Cummings fought five more times through 1983, though he lost all five and was knocked out twice.

Arturo Gatti

Date: July 14, 2007

Site: Atlantic City, New Jersey

Result: L (TKO 7) Alfonso Gomez

Long heralded as the sport’s premier action hero, Gatti had lost two of three fights and was in search of a credible opponent to prove he still had what it took to remain on the biggest stages.

In Gomez, a veteran of “The Contender” reality TV show, the Gatti team saw a slow-handed brawler with something less than consciousness-altering power. A victory over him would have moved “Thunder” closer to what was then an anticipated match with Julio Cesar Chavez Jr.

Once the fight began, though, Gomez was able to start and end exchanges and repeatedly rattle the iron-chinned Gatti with right hands. The match became more and more brutal as it continued, Gomez was ahead on all three scorecards and Gatti was ultimately unable to continue after a knockdown in the seventh round.

He retired immediately, but never had the post-ring career as an ambassador for the sport that many anticipated. Instead, he died after a bizarre domestic incident in July 2009 that was ruled a suicide.

Marvin Hagler

Date: April 6, 1987

Site: Las Vegas, Nevada

Result: L (SD 12) Ray Leonard

It was the night Hagler had waited an entire career for.

But shockingly, once he actually had Ray Leonard in front of him in the ring, things weren’t quite as “Marvelous” and he’d anticipated.

The rejuvenated “Sugar Ray” intermittently scored with flashy flurries and spent much of the 36 minutes on his bicycle, avoiding a slower Hagler who was never able to corner him long enough to dole out the sustained violence that he needed to overcome the idea that Leonard was surviving and thriving.

It went to the scorecards and Hagler wound up on the short end, with two judges awarding Leonard the win and Hagler’s consensus world middleweight championship that went with it. Hagler left the ring disgusted and never fought again, turning down lucrative rematch propositions to move to Italy and make movies.

Sugar Ray Leonard

Date: March 1, 1997

Site: Atlantic City, New Jersey

Result: L (TKO 5) Hector Camacho

A full decade after his return to beat Hagler, Leonard was back on his comeback horse -- this time as a 40-year-old vying for one last run in the spotlight.

Leonard was a 7-to-5 favorite to beat Camacho, and claimed that a one-sided loss to Terry Norris in his most recent fight six years earlier had come thanks to a difficulty in making weight, a fractured rib and emotional upheaval from divorce proceedings.

He faded quickly following a moderately successful first round, was bloodied by a cut over the right eye in the fourth round and was dropped by an uppercut in the fifth. He rose and continued, but a subsequent volley of shots prompted intervention from referee Joe Cortez.

Leonard claimed afterward that his footwork was hampered by a pre-fight calf injury, but didn’t hesitate when asked if the loss to the former 130-pound champion meant the finish line had been reached. “For sure, my career is definitely over," he said.

Joe Louis

Date: October 26, 1951

Site: New York, New York

Result: L (TKO 8) Rocky Marciano

Louis was more than two-and-a-half years past his world championship days, but continued to fight thanks to money concerns.

The prolonged post-championship run eventually brought him to the young, strong Marciano, who was 37-0 at the time and looking for a resume-bolstering victory over a big-name opponent.

Louis was a slight betting favorite at the opening bell and was moderately competitive through the initial seven rounds, winning two on two official scorecards and three on another. But he was dropped by a left hook in the eighth round, rose and was driven through the ropes by a charging Marciano as referee Ruby Goldstein waved off the proceedings.

After the fight, the 37-year-old Louis was blunt. “I saw the right coming, but I couldn’t do anything about it,” Louis said. “I was awfully tired. I’m too old, I guess.” He made $132,000 for the loss, and never fought again.

Mike Tyson

Date: June 11, 2005

Site: Washington, D.C.

Result: L (TKO 6) Kevin McBride

Tyson hadn’t won a fight for more than two years and was almost nine years removed from his last day as a world champion, but he still had his pre-fight bravado.

He referred to opponent Kevin McBride as a “tomato can” and insisted he’d “gut him like a fish,” but the 6-foot-6 “Clones Colossus” proved a far heartier meal than expected.

Tyson was active, but not terribly effective in the early going, and gradually became more and more fatigued after being drawn into clinches in which the taller, heavier McBride could lean on him. He became frustrated in the sixth round, had two points deducted for an intentional head butt and went down from a McBride shove at the end of the round. He quit on his stool between rounds, failing to come out for the seventh.

"I don't have the guts to stay in this sport anymore," Tyson said. "I don't want to disrespect the sport that I love. My heart is not into this anymore. I'm sorry for the fans who paid for this. I wish I could have done better, but it's time to move on with my life and be a father and take care of my children."