Britain's Elinor Barker was pipped to gold at the Track Cycling World Championships as Italy's Rachele Barbieri won the women's scratch race.
Jolien D'Hoore took bronze for Belgium in the 10km race on the opening day of the championships in Hong Kong.
"I went ever so slightly too soon and that probably cost me the win," Wales' Barker, 22, told BBC Sport.
"I was just not fast enough. Congratulations to her but I'm really disappointed."
Barker won team pursuit Olympic gold alongside Katie Archibald, Laura Kenny and Joanna Rowsell Shand in Rio last summer.
But she just missed out on Wednesday as the medals were decided in a bunch sprint and Barbieri edged home.
Elsewhere, there was disappointment for Britain in the men's team sprint.
Jack Carlin, 19, Ryan Owens, 21, and Joseph Truman, 20, were third-fastest in qualifying but failed in their first-round match-up with the Netherlands.
The trio had taken two gold medals from two World Cup meetings in November - their first at senior level - but defeat meant they will miss out on a medal race.
"We've had a dream run up to now and we were close to our best time ever, it's really disappointing," Owens said.
"We came here in the form of our lives, and if a few technical things had gone differently it would have been a different story."
New Zealand retained their title with victory over Netherlands, while France won bronze from Poland.
In the men's team pursuit, Andy Tennant, Mark Stewart, Ollie Wood and Chris Latham qualified for Thursday's bronze-medal race against Italy. Australia and New Zealand will contest the gold medal.
Russia won gold in the women's team sprint, beating Australia, while Germany won bronze from China. Great Britain did not have a team competing in the race.
'A fantastic ride from Barker' - Analysis
BBC cycling commentator Simon Brotherton
What a fantastic ride that was from Elinor Barker. First she had us on the edge of our seats, then she had us out of our seats, but in the end it wasn't quite her day.
Double Olympic gold medallist Joanna Rowsell Shand
With one lap to go, Elinor had got around the Dutch favourite and she probably thought she'd nailed it. The Italian just won it, but El looks so strong and I think we have got a lot more to see from her this week. Starting with a silver will only make her hungrier.
Six-time Olympic gold medallist Sir Chris Hoy
New Zealand were immense in the men's team sprint. It was tough on the British team, but this will inspire them to work harder.
They shouldn't be disappointed though. It's frustrating, but these are the first steps towards the Tokyo Olympic Games and they should be proud of what they have achieved so far. It's been a fantastic breakthrough on the elite international level from them this year.