Whether it is peaking at the right time or getting his hand on the wall first in a close finish, the American has always had an edge over his rivals.
Phelps struggled to maintain his motivation for the relentless grind of training after winning eight gold medals in Beijing, but just as he has done throughout his career, the 27-year-old has timed his run to the London Olympics to perfection.
After suffering defeats at the past two world championships and last month's U.S. Olympic trials, Phelps has rediscovered his passion and form and is back on track for another golden performance.
"He's trained really well since the trials so I think he'll be better than he did there," Phelps' coach Bob Bowman told Reuters at the U.S. team's final pre-Olympic training camp in central France.
"I'm very happy with what he's done. I think he's improved significantly. He's really trained better than he ever did before."
Coming from Bowman, that is high praise indeed as both he and Phelps have always been reluctant to talk up their prospects, but they are not the only ones who have noticed the difference.
Gregg Troy, who is the head coach of the U.S. men's team and also the personal coach of Phelps' biggest rival Ryan Lochte, was also gushing after watching him train.
"From what I've seen, Michael will be outstanding," he told Reuters. "He's going to be ready to go and be a really top competitor."
Phelps and Lochte will clash in the 200 and 400 metres individual medley events in London, where the 2012 Games start on Friday.
At the U.S. trials, Phelps won the 200 IM but Lochte beat him in the 400 IM, setting the stage for an epic showdown in the British capital.
"I'm not frightened of anyone," Phelps replied when asked whether he feared Lochte.
"The only things I'm afraid of are snakes and heights. I don't think Ryan's a snake and I think I'm taller than him.
"I have my goals and I hope to achieve them. It's not going to be easy but if I can accomplish them I'll be pleased. Whether I come first or second or eighth, it doesn't matter."
The pair, friends outside the pool but fierce rivals in the water, were also scheduled to clash in the 200m freestyle but Phelps pulled out.
The idea was partly to conserve his energy for the relays after entering a total of seven events, one less than at the two previous Olympics but still a heavy workload.
"It doesn't change anything at all for me," Lochte said.
"! can't control what he does and there's so many other great swimmers out there. I can't worry about one person.
"If I'm worried about him or anyone else that's going to affect me. I've just got to go out there and race."