BERLIN -- Usain Bolt won the 200-meter semifinals with ease and swagger Wednesday, looking sharp for a possible assault on a second world record at the world championships.
Jamaica didn't have to wait until Bolt's final Thursday for another reggae celebration. Brigitte Foster-Hylton followed some Bolt-like clowning before the race with a clean run to win the 100 hurdles title.
Priscilla Lopes-Schliep of Canada won the silver and Delloreen Ennis-London of Jamaica the bronze. The Americans were outrun again, with Olympic champion Dawn Harper fading to seventh.
The Americans have three golds and eight medals overall, just ahead of Jamaica with three golds and seven total.
Caster Semenya, an 18-year-old South African who has been asked to take a gender test, won the 800 with a stunningly dominating run.
She took the lead halfway through and finished in a world-leading 1 minute, 55.45 seconds, beating defending champion Janeth Jepkosgei of Kenya by a massive 2.45 seconds. Jennifer Meadows of Britain was third.
The world track and field federation requested the gender test for Semenya about three weeks ago after she improved her personal bests by wide margins.
Bolt thrived in the 80-degree heat, running hard on the curve before closing things down just past the halfway mark and cruised past the line in 20.08 seconds. Despite easing up, Bolt still had the fastest qualifying time.
If he had pushed, Bolt could easily have broken Tyson Gay's 2007 championship record of 19.76 seconds. Bolt's world record stands at 19.30.
His performance stood in sharp contrast with his run Tuesday when unseasonably cold weather turned him lethargic.
"I am feeling much better than yesterday," Bolt said.
Defending champion Gay is injured and out of the 200, and American teammate Shawn Crawford had to push hard to qualify third in Bolt's heat.
In the second semifinal heat, Wallace Spearmon of the U.S. finished first in 20.14, edging Steve Mullings of Jamaica.
The temperature is expected to exceed 85 degrees Thursday at the Olympic Stadium, and Bolt loves the heat. He cut through the swelter of Beijing last year on his way to three Olympic golds and as many world records.
Bolt tried to play down expectations of a record every time he lines up in a final. A foot injury slowed his curve running early in the season.
"I really have not done the same amount of work like I did for the 100," Bolt said.
Crawford was so awed by Bolt's 100 record of 9.58 that he thinks his rival can do it again, this time with 19:28.
"My goal is to run 19.51," Crawford said. "I'd be happy with that. He is looking very impressive right now."
Bolt will be looking to give his country a 3-0 edge over the U.S. in the sprints, bringing Jamaica closer to the 5-0 thrashing of Beijing.
Defending 200 champion Allyson Felix easily won her heat to reach Thursday's semifinals. Likewise for Olympic champion Veronica Campbell-Brown of Jamaica. Marshevet Hooker of the U.S. had the fastest qualifying time of 22.51.
After winning three golds at the last world championships in Japan, Felix was upstaged in the Olympic 200 by Campbell-Brown.
In the 1,500, defending champion Bernard Lagat came in third after he was boxed in behind winner Yusuf Saad Kamel of Bahrain and silver medalist Deresse Mekonnen of Ethiopia.
In the decathlon, Oleksiy Kasyanov of Ukraine led after five events. Yunior Diaz of Cuba had a fast 400-meter race, the last event of the day, to squeeze past Trey Hardee of the United States into second place.
Robert Hartig of Germany captured the discus with a throw of 227 feet, 9 inches and then ripped off his shirt in celebration. Piotr Malachowski of Poland won the silver. Olympic and defending world champion Gerd Kanter of Estonia took the bronze.
Olympic champion LaShawn Merritt and defending champion Jeremy Wariner left little doubt the U.S. could count on another gold in Friday's 400 final.
Wariner had dominated the distance since the Athens Games in 2004, but Merritt upset him in Beijing last year to take Olympic gold. Merritt set a world-leading time of 44.37 seconds in his semifinal heat and Wariner coasted in 44.69.
"I wanted to come out today and set the bar, set the tone, finish up good," Merritt said.
What looked like guaranteed gold for Cuba with Dayron Robles in the 110 hurdles suddenly looked shaky when the Olympic champion hit the first obstacle and struggled to get to the semifinals with the slowest qualifying time.
"I am OK," Robles said. "But I have pain that maybe nobody can understand."