Michael Phelps continues his comeback from a ban by swimming the fastest 100m butterfly in the world this year.

The most decorated Olympian of all-time led from start to finish, clocking a stunning 50.45 seconds at the US championships in San Antonio.

Phelps's time, the second-fastest recorded in a standard swimsuit, bettered the 50.56 South African Chad Le Clos clocked to win the same event at the world championships in Russia only hours earlier.

Fellow American Ian Crocker swam 50.40 in 2005, before the introduction of high-tech swimsuits, which were subsequently banned in 2010 after times improved so dramatically they made it impossible to compare eras.

Phelps is competing in San Antonio rather than Kazan because he was banned from the US team after his drink-driving arrest.

But the 18-time Olympic gold medal winner has sworn off alcohol until after next year's Rio Olympics, and his performances the past two days leave no doubt that he is back.

His winning time in the 200m butterfly was also faster than the gold medal time in the same event in Kazan.

"It goes hand in hand with what I've been doing in training. I'm back to actually doing work like I used to and it pays off," Phelps said.

"It's not rocket science but you have to work hard. This is a great start for me to go into next year."

Phelps sounded confident about Rio, but warned the Games were still a long way away.

"A lot can happen in a year, with not only myself but everybody else in the world.

"Hopefully I can keep this going over the span of the next year."

Source: Reuters