Former Olympic champion Roman Sebrle has pulled out of the decathlon after aggravating a foot injury in the first event.
The 37-year-old Czech ran with a heel problem in the opening 100m and finished as the slowest athlete in 11.54 seconds.
"The 100m was OK with the pain but not with the time," Sebrle said. "For the long jump, I couldn't run."
Briton Daniel Awde also withdrew after injuring his knee in the long jump.
The 24-year-old had set a personal best of 10.71secs in the 100m to lie seventh overall before suffering from a flare-up of tendinitis in the second event.
Awde recorded two fouls in the long jump as he battled a knee problem
"If I continued it would probably rupture," Awde said. "If you spoke to me at the start of the year I wouldn't have expected to be here in the first place, it's been a real bane of my life for the last two years.
"I was so ready to put on a good show and entertain the crowd. I was ready but my knee wasn't."
Sebrle was a higher profile casualty as he won the Olympic decathlon in 2004 and took silver in Beijing.
He had also held the decathlon world record for almost 11 years before it was eclipsed by
American Ashton Eaton
in June when he shaved 13 points off Sebrle's best with a new mark of 9,039 points.
BBC athletics commentator Steve Cram suggested Sebrle could now consider calling time on his "fantastic" career.