Tyson Gay stayed on course for a world championship sprint double in Osaka on Wednesday by qualifying fastest for Thursday's 200 metres final.
The American, who won gold in the 100m, coasted home in 20.00 seconds in the second semi-final with Jamaica's Usain Bolt winning the first in 20.03.
Gay, inspired by Sunday's victory over 100m world record holder Asafa Powell, cruised home despite feeling a twinge in his left hamstring coming out of the blocks.
"I had a little [hamstring] trouble at the start and in the curve," Gay told reporters. "Whatever I've got left in the tank is for the final. I'm going to give it all I've got."
Wallace Spearmon, Gay's training partner and 2005 world silver medallist, was second behind Bolt in 20.05 and both will be expected to push Gay in the final.
American Rodney Martin finished third in 20.18 with Churandy Martina qualifying for the final in fourth in a national record of 20.20 for Netherlands Antilles.
Jamaica's Marvin Anderson trailed Gay home in the second semi-final in 20.06 with fellow countryman Christopher Williams third in 20.24 and Greek Anastasios Gousis qualifying in 20.33.