MESA, Arizona (AFP) - Michael Phelps might be rusty after a 20-month layoff, but rival Ryan Lochte says the swimming superstar will always be able to count on his racer's instincts.
"Any race he swims, he's going to make the other swimmers hurt," Lochte said. "That's what he does - he's a racer."
Lochte managed to get his hand on the wall ahead of Phelps in the 100m butterfly final at the Mesa Grand Prix on Thursday, Phelps's first final since the 2012 Olympics.
Phelps retired after the London Games after a stellar career in which he won 22 Olympic medals - an astounding 18 of them gold.
The pinnacle of the US superstar's Olympic career came in Beijing in 2008, when he won eight gold medals in eight events.
Phelps insists he isn't yet sure if his comeback will take him to a fifth Games at Rio in 2016, but his fellow swimmers were as thrilled as fans to see him back on the blocks.
That was particularly true of Lochte, who has had some memorable medley battles with his Olympic teammate.
"Racing against Michael is probably the hardest thing to do," Lochte said. "I love it."
American Katie Ledecky, who won 800m freestyle gold in London, said the meeting - the fourth of six Grand Prix events that lead up to the US championships in August - had a different feel with Phelps around.
"For sure it definitely adds some extra energy to the meet," she said. "Swimmers are real excited about it, too."
Natalie Coughlin, a 12-time Olympic medallist who is still swimming at the age of 31, was delighted to see 28-year-old Phelps back in action.
She took a break of similar length after the 2008 Olympics, although she said her situation was different because "I knew I was coming back".
She thinks Phelps has plenty of good years left in him. "He's so young and he's enjoying it, so why not?" Coughlin said.
Phelps seemed taken aback when asked about the welcome from his peers - particularly Lochte's comment that his heart "broke a little" when Phelps retired.
"I don't know what to say," Phelps said. "This sport has given me so much and I don't think I can do enough to give back to this sport what I've received from it."