Phoenix - Olympic superstar Michael Phelps's legendary racing instincts kicked in on Saturday as he capped his latest comeback meet with a storming 100m freestyle win.
Phelps flew from last to first on the second lap for his second victory of the Mesa Pro Series meeting - his first competition in eight months.
Swimming in lane seven after posting the fifth-fastest qualifying time, Phelps clocked 49.72 to edge top qualifier Ryan Lochte by five-hundredths of a second.
Conor Dwyer made it a US sweep of the top three places with a time of 50.02.
The dramatic win for the 18-time Olympic gold medalist came less than half an hour after he finished third in the 200m individual medley behind Lochte and Dwyer.
Phelps, whose glittering Olympic career was built on multi-event campaigns such as the one that yielded a perfect eight golds in eight events in Beijing in 2008, admitted before the finals he didn't know how his body would cope with the double.
"Being able to come back and do that 100 free, that was the best day of my meet here," Phelps said. "I don't know if having a tight turnaround like that is better for me.
The 29-year-old last raced in August, and was coming off the six-month suspension imposed after his drunk-driving arrest in September.
"It's weird. I feel so much better in physical shape, but I almost don't know how to race," Phelps mused before Saturday's finals.
The knack seemed to come back to him on the final lap of the free, and Phelps exited the pool with a big grin to the cheers of an enthusiastic crowd.
"I don't know what it was coming of the 50 wall," Phelps said. "As I was underwater I just started kicking and it was like, one of the kicks I felt something different.
"Moving past the kid in the lane next to me I was like, 'I'm starting to move here, this is a pretty good feeling.'"
The feeling had been lacking even as Phelps opened the meet on Thursday with a 100m butterfly victory.
He failed to qualify for the final in the unfamiliar 400m free and scratched from the 100m backstroke before closing the meet in suburban Phoenix with two podium finishes.
Phelps's longtime coach Bob Bowman was delighted with the "spark" he saw on Saturday.
And both Phelps and Bowman said this week's results are a good baseline to gauge his progress as Phelps builds toward a 2016 Rio Olympic bid.
"It's a good start," Phelps said.
In other events, Hungary's "Iron Lady" Katinka Hosszu earned her third win of the week in the women's 200m individual medley.
Hosszu clocked 2:11.40, with American Caitlin Leverenz second in 2:12.59.
Arkady Vyatchanin, a former Russian Olympian who is pursuing Serbian citizenship, won the men's 200m backstroke with a time of 1:56.95 - seventh-fastest in the world this year.
Zimbabwe's Kirsty Coventry, a two-time Olympic gold medallist, rallied to win the women's 200m backstroke in 2:12.05, edging Hosszu for the gold.
World record-holder Katie Ledecky won the women's 800m freestyle in 8:13.02, well off her 2015 world-leading 8:11.21 but good for her fourth freestyle victory of the week after wins in the 1 500m, 400m and 200m.
She opted out of the 100m free final on Saturday night, which was won by the Bahamas' Arianna Vanderpool-Wallace in 54.18.