Michael Phelps continued his brilliant comeback when he swam the fastest time in the world this year to win the 200 metres individual medley at the US championships in San Antonio.
He clocked one minute 54.75 seconds, significantly faster than fellow American Ryan Lochte swam to win the world championships in Russia in 1:55.81 on Thursday.
I've been away from the sport for a while and I feel like I'm kind of back where I used to be
Lochte holds the world record of 1:54.00 from 2011.
After winning the 200m and 100m butterfly in 2015-world leading times on Friday and Saturday, respectively, there was no doubt that Phelps was back near his best form.
His Sunday performance was further confirmation that in Rio next year he could add to his record 18 Olympic golds.
"I feel so old it's kind of wild," Phelps, 30, said.
"I've been away from the sport for a while and I feel like I'm kind of back where I used to be. It's good to be here."
Either Phelps or Lochte has held the world record since 2003.
Phelps, who has three Olympic golds in the event and whose best time of 1:54.23 came at the 2008 Beijing Games, said the event would probably be in his 2016 Olympic plans.
Phelps is swimming at the US nationals instead of the world championships because he was banned from the US team after his drink driving arrest last year.
He is under supervised probation for 18 months and under orders from the judge who ruled in his case to abstain from alcohol for that period, something he has vowed to do until after the Rio Games.