Academy: Pool king Phelps

The 19-year-old, whose eight medals at Athens included six golds, led from the start in Indianapolis and pulled away to win in one minute 43.59 seconds.

The time broke the American 200m free short course record of 1:44.10 set by Josh Davis at Athens in 2000.

Fastest qualifier Rick Say, of Canada, was second in 1:44.39.

Phelps, making his first competitive appearance since the Games, said: "I wanted to get out that first 100m. I knew Rick was going too.

There's probably going to be a lot of tough races ahead, so I'm glad I have one under the belt Michael Phelps

"I wanted to go out with him. I had a good feeling about the first 100m.

"There are a few things I would change about that race but I'll take it. I wanted to go 1:44. I achieved my goal and I am pretty happy right now.

"There's probably going to be a lot of tough races ahead, so I'm glad I have one under the belt."

Phelps also plans to swim the 400 individual medley on Friday, the 200m individual medley on Saturday, the 100 individual medley on Sunday and the 200m butterfly on Monday.

Meanwhile, James Hickman booked his place in Friday's final of the men's 100m butterfly.

I will be looking for some good rest and more improvements to put myself in with a shout of a medal James Hickman

The Briton won his semi-final at the Conseco Fieldhouse in 51.69 to qualify second fastest behind American Ian Crocker who clocked the quickest time of 50.61.

"It felt good. It was faster than the heats and that is what I wanted," said Hickman.

"All of the things I wanted to improve on, my stroke rate, speed and the turns, I did and it saw me go quicker.

"I will be looking for some good rest and more improvements to put myself in with a shout of a medal."

Elsewhere, Australian teenager Jade Edmistone , who set the world short course record of 29.90 last month, led 50 breaststroke finalists in a time of 30.01.

American Tara Kirk was second in 30.61.