Liu Xiang burst onto the world championships stage yesterday with a solid 110m hurdles heat as a tired Veronica Campbell bounced back in her bid for a sprint double.
Liu, the undisputed favorite and one of the biggest draws here, ran through his heat in 13.26 seconds to qualify for today's semi-finals.
But his teammate Shi Dongpeng upstaged him, flying over the barriers in 13.22 seconds.
"This is a preliminary so there's no need to run too fast," Liu said. "I'm just trying to get to the finals. I'm aiming for a range of about 13.10 to 13.30 for the preliminaries."
Liu was still quicker than France's world title holder Ladji Doucoure (13.61) and US rival Terence Trammell, who won his heat in 13.41.
Women's 100m champion Campbell was back on the track in the 200m heats but said she was feeling the pace after winning her qualifier in 22.87 seconds, ahead of arch-rival Torri Edwards of the US.
"I'm tired, but by the final I will be ok," the Jamaican said.
Reigning champion Allyson Felix was the fastest through the heats in 22.50 and the American said it was a relief to finally get going.
"I wanted to get out there on the track and get my legs moving," she said. "It felt great. I did it as easy as possible and it was decent. The fact that a lot of people see me as the favorite puts a little pressure on me, but I have high expectations myself."
Also safely through to the semi-finals was Felix's US teammate Sanya Richards.
Another five gold medals are decided on day five of the championships, including the men's high jump and 1,500m, and the women's discus throw, 100m hurdles and 400m.
The favorite in the 1,500m is Bahraini athlete and defending champion Rashid Ramzi, who was born in Morocco.
He coasted through his heats and looks to have rediscovered the fire that was missing over the past year.
American Bernard Lagat will lead a US push to derail Ramzi's gold medal drive.
"I'm improving from one race to another, so it is a good sign for the final," said Ramzi, who is also the defending 800m champion. "I hope for a fast race in the final, because I can have a bigger impact."
Another Bahraini, Maryam Yusuf Jamal, began her historic quest to win a first-ever world or Olympics medal by a female Gulf athlete.
Jamal finished the 1,500m heats second fastest in 4:09.47.
The only woman ahead of the world No. 1 was Morocco's Mariem Alaoui Selsouli (4:09.05), with Russia's Yuliya Chizhenko and Yelena Soboleva not far behind.
"My race was okay," said the 22-year-old, who was literally bundled out of a medal at the last world championships when a nudge from Chizhenko sent her reeling with 250m to go.
"My strongest competitors will be the Russians, I guess, although, as we saw in the 800m race, they did not do as well as expected in the final," she said.
The women's 400m looks like it could be an unexpected showdown between Novlene Williams of Jamaica and Britain's Nicola Sanders.
Williams won her semi-final with a season's best 49.66 to go third on this year's rankings.