The notion would sound preposterous if the comeback didn't happen over the weekend.

But did Michael Phelps' DUI last fall save his swimming career?

USA TODAY Sports reported Sunday that Phelps returned to competitive swimming at the Arena Pro Series Swim event in Mesa, Ariz. after a six month suspension because of his DUI charge and had a more than promising return.

The most decorated Olympian in swimming history with 22 medals and 18 gold during his career, Phelps swam in four events.

Michael Phelps says he is swimming his fastest practice times since 2008

He won the 100 butterfly, his signature event, in a time of 52.38 seconds on Thursday. He competed in the 400 freestyle but failed to advance past the preliminaries.

Phelps finished third in the 200 individual medley in 2:00.01 on Saturday but saved his best, apparently, for the 100 freestyle just 25 minutes later.

He hit the turn in last place but came back to pass the entire field, including longtime rival Ryan Lochte to win in a time of 49.72 seconds.

"I don't know what it was, coming off the 50 wall," Phelps said. "As soon as I was underwater, I just started kicking and it was like, one of the kicks I just felt something different that I hadn't felt before. I don't know if that was switching a gear into knowing how to race again or what, but it was something I hadn't felt before since I've been back in the water."

Only a year ago, Phelps unretired, eyeing a bid in the 2016 Summer Olympics in Rio de Janeiro. But if his DUI five months later is any indication, the passion to get back in the water still seemed lacking.

When he came out of his suspension, he said he was a changed man. As least for one meet, he sounded like it.

"Being back in the water racing is something that I love, something that I really do enjoy," Phelps said. "It does feel really good to be back."

But he also sounds as if he understands how to become great this time around, which is different from his previous stints.

"I'm not 21 anymore. I'm not the same as I once was," he said, according to the Washington Post. "Where you could get by on getting three, four hours of sleep and coming in to work out in the morning, now I don't know if I'm ever up past 11 o'clock. I have to have seven, eight hours to function the next day."

So while his times are three seconds off his world record pace (he swam a 49.82-second time in the 100 butterfly in 2009), Phelps finally may have the fire to get more medals in Rio in the summer of 2016.