Fourth place in the men's sprint for Jason Kenny capped a forgettable day for Great Britain at the European Track Cycling Championships in Apeldoorn.
Kenny, 23, lost his semi-final to Germany's Maximilian Levy after a fall and was then beaten to bronze by Russia's Denis Dmitriev.
"It's frustrating but I haven't shown great speed in training," said Kenny.
Chris Hoy earlier pulled out with a chest infection and Victoria Pendleton lost in the women's quarter-finals.
Jess Varnish failed to make it past the last 16 on a far quieter day for Britain following the success of Friday's opening races, in which the team won three gold medals.
Kenny and Hoy are fighting for the one individual sprint place available at the London Olympics following rule changes from world governing body the UCI.
Neither man has had the easiest 24 hours - Kenny slipping in the men's team sprint, Hoy failing to overcome illness - and Kenny's poor luck continued as he fell in the third and deciding heat of semi-final against Levy.
Under track cycling's rules the heat was re-run but, although Kenny ran the German close, Levy picked up the win before losing out to France's Kevin Sireau for gold.
Dmitriev always looked to have the edge on Kenny in the bronze race-off and the Russian came away with the medal in back-to-back victories.
"I would have liked a medal but that's the way it is," Kenny told BBC Sport.
"I think I got the maximum out of myself in qualifying. I'm disappointed to miss out on the podium by one place but it was good to be competitive."
Of his semi-final fall, Kenny said: "I changed direction too quickly and sent myself off the bike. It's not the grippiest track in the world and you've got to be aware of that when you're racing.
"It hasn't been [the easiest couple of days] but people are going to fall off, we're going to make mistakes at the start. Hopefully we'll get it out of our system and not make the same mistakes twice, and by the time we come round to the Worlds and the Olympics we'll be our usual well-drilled machine."
Having won team sprint gold alongside Varnish on Friday, Pendleton had to fight to reach the women's individual sprint quarter-finals, coming through the repechage after the last 16.
But Ukrainian rival Lyubov Shulika, beaten by the British duo in that team sprint final, exacted revenge with a 2-0 victory over the 31-year-old in the best-of-three format.
Pendleton, who won four consecutive sprint world titles alongside Olympic gold between 2007 and 2010, finished the night in eighth place, while Shulika defeated Olga Panarina of Belarus to win the women's title.
British Cycling performance director Dave Brailsford, like Kenny, moved to play down the significance of results in the Netherlands.
"There's a lot more to come [from Pendleton]," he said. "She's got a big block of work coming up now and it's important she gets some consistency.
"What she needs now is a real, long block of uninterrupted, consistent work, and she'll be fine by the time we get to August.
"There's no point judging her on what's here because it's part of a process. Everybody has got more to come."
Varnish's competition ended when the 20-year-old finished behind Pendleton in their repechage heat, from which only one rider can progress.
Hoy finished fourth-fastest in the morning session's qualification ride before deciding to pull out, and is highly unlikely to take part in Sunday's keirin, the last of his three events to be staged.
Pendleton should be a contender for the women's keirin title while Britain has Ed Clancy in the men's omnium and Laura Trott in the women's equivalent, all of which conclude on Sunday.
Clancy sits in third after three of the omnium's six events, spread over two days of racing, as does Trott - who looked superb in winning the women's omnium elimination race, the high point of Britain's racing on Saturday.