Three-time Olympic champion Jason Kenny crashed out of the men's keirin on the second night of competition at the Track World Cup in Glasgow.
Kenny is the natural heir to Sir Chris Hoy and was seeking victory in the event the Scot has dominated in recent years in the venue which bares his name.
The 24-year-old Olympic sprint champion was supreme in the early rounds, but had to wait for his chance in the final due to a temperamental motor-paced Derny bike.
When the race did get under way at the third attempt, Kenny was well positioned with one lap to go and was making his move on the back straight when he lost his balance and tumbled to the track.
Kenny took Quentin Lafargue with him and both riders were quickly on their feet nursing skin abrasions. Kenny, who is scheduled to ride in the sprint on Sunday, was able to ride around to show there was no significant damage, while the Frenchman was assessed by medical staff.
Stefan Boetticher of Germany won ahead of Peter Lewis (Jayco) and Takashi Sakamoto (Japan).
Earlier, Jess Varnish took silver in the women's sprint as Germany's Kristina Vogel claimed a 2-0 win in the final.
Becky James, beaten by Varnish in the semi-final, claimed a 2-1 win in the bronze medal ride-off against Hong Kong's Lee Wai Sze.
Varnish and James won the team sprint title on the opening day and will ride the keirin on Sunday's final day of competition.