By Steve Keating

KINGSTON, Jamaica (Reuters) - Just 12 hours after Yohan Blake claimed a shock win over world record holder Usain Bolt in the 100 meters, the two training partners were back in the starting blocks and on a 200m collision course at the Jamaican Olympic trials on Saturday.

The pair had early starts for the 200m preliminary heats at an empty National Stadium, a stark contrast to the electrifying atmosphere at the seething track on Friday evening.

With only an uninterested cleaning crew sweeping up debris, the media, and a few family and friends looking on, Bolt shot from the blocks then quickly shut down strolling across the finish line in a winning time of 21.21, more than two seconds off his world record.

Asked if he was heading back to bed after his 0900 start, Bolt laughed, "of course man" as he threw a white towel over his head and made his way to the exit before Blake had even finished his heat.

Running in a heat with just four starters, Blake also had little need to expend much effort on a muggy, hot morning with the first four in each race advancing to semi-finals later on Saturday.

Blake claimed the Jamaican 100 crown in a dazzling 9.75 seconds, a personal best and fastest time in the world this year but barely got out of first gear in his 200 heat crossing first in 21.43.

Nicknamed "The Beast", Blake was all business saying he had had little time to savor his 100m performance, before quickly refocusing on the 200m.

"I think maybe everyone was surprised (with the 100m win) but I wasn't," said Blake. "You have to refocus again and know you're not finished until after the Olympics."

The 200m is expected to be an even more competitive race between the two training partners, who own the two fastest times in the event, Bolt holding the world record of 19.19 followed by Blake on 19.26.

The final on Sunday will close the four-day meeting with the top three finishers all earning spots on the Jamaican squad for the London Summer Games.

(Editing by Ossian Shine)