Muhammad Ali had 61 fights in a professional career that touched three decades, including 22 triumphs in heavyweight title bouts.

So if you're searching for meaningful performances on the ring's biggest stage, he provided loads of material.

But the evidence presented to back up his case as history's all-time best big man was perhaps strongest in a handful of those appearances.

To honor his memory, here's one man's list of Ali's top five greatest bouts:

Feb. 25, 1964 -- TKO win over Sonny Liston (Round 7)

A 22-year-old kid against a veteran champion who'd spent the previous 17 months terrorizing the heavyweight division?

It's little wonder that bookmakers made Ali - then known as Cassius Clay - a 7-to-1 underdog.

But it didn't take long for them to see the error of their ways.

After dominating the run-up with his mouth, the "Louisville Lip" outclassed Liston with his fists, confounding the slower man with speed and movement and ultimately prompting his surrender -- though the company line was an injured shoulder -- before the start of Round 7.

March 8, 1971 -- Unanimous decision loss to Joe Frazier (15 rounds)

A loss as one of his greatest fights? Surely you can't be serious.

Actually, yes.

Considering he'd fought just 18 rounds in the previous three-plus years, the idea that Ali could go the full 15 with a ferociously prime version of "Smokin' Joe" is testament to his prowess.

And the fact that he rose from the deck after taking a left hook for the ages in the final round revealed a heart that few gave him credit for amid all the chatter.

Frazier deserved the unanimous verdict he got that night, but he never reached that level again.

Oct. 30, 1974 -- KO win over George Foreman (Round 8)

Ten years after he'd taken down a fearsome Liston, a 32-year-old Ali traveled a similar path -- this time to the wilds of Zaire -- to meet a 25-year-old Foreman, who arrived with 37 wins, 34 knockouts and two-round erasures of the only two men -- Frazier and Ken Norton -- who'd beaten Ali.

But where others saw calamity, the old man saw opportunity.

His passive "Rope-a-Dope" resistance gradually drained the strength from a quick-starting Foreman, and by the time Round 8 arrived, the younger man was both out of gas and out of luck.

Ali's flurry from the corner and Foreman's staggering tumble to the canvas remain among the sport's iconic images, even 40-plus years later.

Oct. 1, 1975 -- TKO win over Joe Frazier (Round 14)

The climatic fight in the trilogy by which all others are measured.

Though Ali was an aging champion and Frazier had seemingly hit the skids by the time their third fight arrived, the two men once again succeeded in pushing each other to the outermost limits.

The aptly-named "Thrilla in Manila" was competitive in the early going before Ali took control in the later rounds and ultimately prompted Frazier's legendary chief second, Eddie Futch, to surrender on his man's behalf before the final round.

Still, though he was the stoppage winner, Ali later called it the closest thing to death he'd ever experienced. And if ever two men were made for one-on-one combat, it was these two.

Sept. 15, 1978 -- Unanimous decision win over Leon Spinks (Round 15)

Most Ali fans will tell you they'd have rather he walked away after winning the Frazier series.

But he fought on, defending his title six more times before losing to a gap-toothed novice just seven fights past a gold medal win at the 1976 Summer Olympics in Montreal.

And if he hadn't lost to the 24-year-old Spinks, those same fans would have missed out on the boxing clinic he administered in a rematch seven months later.

A 36-year-old Ali took 10, 10 and 11 of 15 rounds on the three official scorecards and became the first man to win the heavyweight title three times.

"I killed myself to get ready for Spinks. I suffered and sacrificed more than I ever did. There's nothing left for me to gain by fighting," he said afterward.

Muhammad Ali's win over George Foreman was one of patience. Getty Images