Kelly Sotherton admitted she was "gutted" after ending day one of her quest for Olympic gold in the heptathlon in third place in Beijing.
Sotherton, bronze medallist in Athens four years ago, recorded personal bests in the first and last events of the day - the 100m metres hurdles and 200m - but was disappointed with her performance in the high jump and shot.
"I am so disappointed, I'm really gutted," Sotherton said. "I am in much better shape than that. I'm really hard on myself though. Maybe it's because it's my first heptathlon of the year. I have just not taken advantage of the situation."
That was a reference to the absence of defending champion and undisputed world number one Carolina Kluft, the Swedish star opting to contest the long jump and triple jump instead.
Sotherton looked in good shape after setting a personal best of 13.18 seconds in the 100m hurdles and clearing a solid 1.83m in the high jump.
But the 31-year-old could then only manage a best of 13.87m with her first attempt in the shot this evening, 0.79m down on her personal best, and was unhappy with running 23.39 in the 200m - 0.01s quicker than her previous best.
"Overall it's a solid performance, it's kind of just average for me," she added on the BBC. "I'm in the mix but I expected to win that 200 in under 23 seconds.
"It's another day tomorrow."
Sotherton will contest the long jump, javelin and 800m tomorrow, trailing leader Hyleas Fountain by 122 points with Ukraine's Nataliia Dobrynska in second courtesy of a world heptathlon record of 17.29m in the shot. Britain's Julie Hollman was down in 33rd place.
In the men's 100m, star trio Usain Bolt, Asafa Powell and Tyson Gay all cruised through to tomorrow's semi-finals but only Tyrone Edgar made it through for Britain as Simeon Williamson and Craig Pickering went out.
Williamson was fourth in his heat in 10.32 and Pickering fifth behind Bolt in 10.18, but Edgar continued his impressive form from this morning with a time of 10.10 in heat three.
World record holder Bolt looked in awesome form as he strolled to victory in 9.92s, despite spending most of the last 50m looking around at the rest of the field.
Powell clocked 10.02s in the final heat while world champion Gay looked to be working a bit harder than the others in finishing second in his heat in 10.09s.
Edgar, who finished fourth in the trials but benefited from Dwain Chambers failing to overturn his Olympic ban, said: "I've come to the Olympic Games and have made the semi-final, now I just want to go home and sleep and get ready for the semi-final and hopefully surprise everybody and make the final.
"I didn't feel intimidated, I belong there in that company. I'm very confident and if I can make a good start I know I can make it."
In contrast, Pickering was "gutted" to miss out after being drawn in the same heat as Bolt, Portugal's Francis Obikwelu and American Darvis Patton.
"That's been my luck this year, I am just distraught," he said. "I knew it was going to be a tough task with the world record holder, the European number one and the American number three in the same heat and my aim was to come fourth and qualify as the fastest loser.
"I'm gutted with the whole year, I've pulled my hamstring twice and now I was screwed up by the lane draw which I don't think I deserved. But I'm a professional, I am going to allow myself just five minutes to wallow in it and then I'm going to pick myself up and focus on the relay."
In the 1,500m Britain's Andy Baddeley eased through to the semi-finals with a well-judged third place in his heat, but team-mate Tom Lancashire missed out after finishing seventh in his race.
Baddeley ran the first two laps at the back of the pack before slowly moving through the field and finished in lane three as he battled to find some space on the track.
The 26-year-old's chances of a medal have been talked up by Sebastian Coe, who believes there is no clear favourite in the 1,500m, and Dream Mile winner Baddeley said: "He's right, there is no outright favourite but at the moment I am only in the semis and there is a long way to go yet. I'm treating that as the next final so I am not looking any further ahead.
"It felt good and I'm really pleased with that. There has been a lot of waiting and that has been quite nerve wracking but once I got out there I felt really good."
Helen Clitheroe ran a personal best and new British record in the 3,000m steeplechase but missed out on the final by just over half a second.
"I was expecting to have to run a personal best to be within a sniff of qualifying so I am very pleased I've done that but I just wished I had made it to the final," she said after a run of 9:29.14 improved her PB by almost eight seconds.
Team-mate Barbara Parker also failed to advance but Ireland's Roisin McGettigan went through after finishing second in her heat in 9:28.92.