"It's impossible for me to get a medal," Liu said through a translator after running 7.79 seconds in his first international championship since an Achilles tendon injury left him unable to start the 2008 Beijing Olympics.

"The tendon is sore," said Liu, whose time was only the 15th fastest of the day. "There is no power.

"I only want to go to the final," said Liu, the 2004 Olympic champion and former world outdoor record holder.

Americans David Oliver and Terrence Trammell both ran 7.60 seconds to lead qualifying.

British European champion Dwain Chambers showed he was the man to beat in the men's 60 meters, clocking a fast 6.59 seconds in his opening race.

"I did not show 100 percent of me," said Chambers, who became the favorite for the title when US champion Ivory Williams tested positive for marijuana and was declared ineligible for the championships.

"It is not about doing big things in the heats but in the final," added the 2008 silver medallist.

Australian Olympic and world champion Steve Hooker turned his first indoor pole vault of the year into an easy qualifier, joining eight others in Saturday's final by clearing 5.60 on his only attempt.

However, the year's top indoor vaulter, France's Renaud Lavillenie, could not advance past the opening session of the three-day championships.

The world outdoor bronze medallist failed three times at the qualifying height.

"I jumped just before the equipment broke, so that made it much easier," Hooker said after the competition was interrupted because of a problem with one of the standards on which the bar rests.

"Anyone that had to jump after that, it made it very challenging. I really feel for those guys." Lavillenie and US 2004 Olympic champion Tim Mack were among the victims, both ending their day at 5.45 meters.

"I spent 30 minutes without jumping at 5.60," Lavillenie said of his failure.

There were problems too for Russian pole vault queen Yelena Isinbayeva, who barely made it to Sunday's final, clearing the qualifying height on her final attempt at 4.55 meters.

Heavily favored defending women's high jump champion Blanka Vlasic of Croatia smoothly advanced to Saturday's final, clearing all three heights she attempted.

Champion Christian Cantwell joined Germany's Ralf Bartels in qualifying for Saturday's men's shot put final.

Bartels, the 2006 European champion, had a heave of 20.91 meters on his second attempt while American Cantwell threw only once, reaching 20.72 to meet the automatic qualifying standard.