LONDON (Reuters) - Trinidad and Tobago's George Bovell turned on the afterburners to win the opening round of the men's 50 metres freestyle at the London Olympics on Thursday.

The 29-year-old powered his way down the pool in 21.77 seconds to win his morning heat and advance to the semi-finals as the fastest of the 16 qualifiers.

Cesar Cielo of Brazil, the defending champion and world record holder, was second fastest, touching the wall in 21.80 seconds to safely move through to the next phase.

"It was enough to get through," he said. "I wasn't thinking of the podium, I was concentrated on qualifying."

Brazil's Bruno Fratus was third quickest while Anthony Ervin of the United States was fourth in his comeback to the Olympics.

Ervin won the gold medal at the 2000 Sydney Olympics but quit the sport three years later, saying he was fed up and wanted to find more meaning in his life. He only decided to make a comeback last year.

Australia's James Magnussen, who was beaten by 0.01 seconds in Wednesday's 100 final, was back in the pool for the single-lap splash and dash, qualifying 10th.

"If I'm being totally honest the last thing I wanted to do this morning was get up and swim again," he said.

"I think once I got over that mental hurdle the swimming felt alright.

"I just want to relax and enjoy this one for what it is. It's an Olympics and I want to have some fond memories of it."

(Reporting by Julian Linden; Editing by Greg Stutchbury)

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