United States of America's Tyson Gay reacts as he wins the gold medal in the final of the men's 100m dash at the World Athletics Championships yesterday. - AP

OSAKA, Japan (Reuters):

Like a good son, Tyson Gay listened to his mother's advice and became the men's 100m world champion yesterday.

"I was having lots of negative thoughts," Gay said of the anxious hours before his eagerly anticipated final showdown with Jamaican Asafa Powell at the World Championships.

Then he talked to his mother.

"She told me to make myself a believer," Gay told reporters.

That the American sprint king did, roaring past Powell to claim his first global title.

Gay clocked 9.85 seconds for the victory with Bahamian Derrick Atkins a surprising second in 9.91 seconds. Powell faded to third in 9.96.

"It's the happiest day in my life," said Gay, who will now try to win the 200 metres and a third gold in the 4x100 metres relay.

"My start was excellent," the Kentucky thoroughbred said, "and about 70 metres I knew I had a great chance of winning".

With 10 metres to go, he knew he had won.

"I just ran hard to the finish line," Gay said.

The loss was a major setback for Powell, who has never won a global title despite having clocked a world record 9.77 seconds three times.

Despite his new crown, Gay would not describe himself as the favourite for the 2008 Beijing Olympics.

"Beijing is another year," he said.

"I am looking forward to racing Atkins and Asafa. He's still the world record holder, hands down.

"He got a medal, I got a medal. I just happened to be victorious this time."