Dix on Bolt's plate at Worlds

The victory, in a wind-assisted 19.95 seconds, completed a sprint double for Dix, who won bronze medals in the 100 and 200 metres at the 2008 Olympics where Jamaican Bolt swept to World records in both. "I can't really see myself losing," Dix said of the upcoming World Championships in Daegu, South Korea.

"Usain Bolt, Asafa Powell, whoever is there I am going to give them a good shot," Dix said. "I am confident I can win the gold after what I did today."

Dix, who won the US 100-metre title on Friday, became the first to claim both national championships since Tyson Gay in 2007. The wins came with little speed training, Dix said.

Doc Patton was a close second in 19.98 with Jeremy Dodson claiming the third spot on the US team for the world championships.

Shalonda Solomon ran down favourite Carmelita Jeter for a shock victory in the wom-en's 200M. Solomon finished in 22.15 seconds, the year's fastest time, to defeat US 100 metres champion Jeter by eight hundredths of a second. Jeneba Tarmoh took third in 22.28.

World 400 metres champion Sanya Richards-Ross finished seventh, ending her chances of running a 200-400 double at the World Championships. Three other 2011 world-leading performances came on the sun-splashed concluding day of the trials.

Kellie Wells topped a world-class 100 metres hurdles field in 12.50 seconds, outrunning Danielle Carruthers and Olympic champion Dawn Harper.  Lolo Jones's run of bad luck continued when she failed to advance past the semifinals after a poor start and then hitting arms with competitors.

The US demonstrated its jump power with both World long jump champion Brittney Reese and high jumper Jesse Williams delivering 2011 bests.  Reese became the year's first women's longer jumper to exceed seven metres as she leaped 7.19. Williams soared to a lifetime best on his final try at 2.37 metres. Only two Americans have ever jumped higher outdoors.

Adam Nelson, the 2005 World shot put champion, came close to another season leader with a heave of 22.09 metres to pace a powerhouse US team for the event.