Italy's Giorgia Bronzini defended her women's road race world title in a sprint finish as a crash ruined British hopes in Copenhagen on Saturday.
Bronzini outsprinted the Netherlands' Marianne Vos for gold after Canadian Clara Hughes' break had been caught.
But a crash further back held up Lizzie Armitstead, robbing a well-set British team of a medal chance. Nicole Cooke finished fourth and Armitstead seventh.
"I'm gutted. I felt good but got caught behind the crash," said Armitstead.
"I felt so good all day but that's cycling, I guess," she told BBC Sport. "A girl came down in front of me after the girls had set me up perfectly, it's such a stupid way to lose it."
Cooke, the defending Olympic champion, said: "We were all riding for Lizzie. She'd been doing so well and I was up there waiting for her to come up to me, but I never saw her.
"So in the end I had to just do my sprint. When we went around the last corner I thought, 'Well, I'm in a race-winning position, Lizzie's either on my wheel or she's not.'
"We're all pretty honest in the team and we want someone from the team to win, it doesn't matter who in the end. If she saw me in that position she'd want me to go for it, positions like that don't just come along."
Cooke eventually finished behind bronze medallist Ina Teutenberg of Germany, having tried to pace herself behind Vos, who cruelly finished second for a fifth consecutive year.
Vos herself suffered in the closing stages, becoming boxed in by Teutenberg and others with 100m to go, which Cooke believes in turn denied her a shot at the podium.
"I used Vos as my reference - which is a pretty good reference point - then she got passed by Bronzini and boxed in really badly," explained the 28-year-old.
"We were both able to re-accelerate but she couldn't reach first and I couldn't get on the podium.
"We're a team that races to win and we rode really, really well. It's a shame we don't have a medal to finish off that work, because it was a fantastic race for us today."
The opening seven laps of a flat, sheltered 14km course to the north of Copenhagen offered very little to suggest how the race might pan out.
Only on lap eight of 10 did a cagey, tactical contest grind into life, when Hughes - the Olympic road race bronze medallist at Atlanta 1996, who embarked on a successful speed skating career before returning to cycling in November last year - made the first real break from the peloton.
The Canadian extended her initial 36-second gap to 38 seconds by the time she began the final lap, but Hughes, 39 on Tuesday, was swallowed up as the Dutch led a perfectly timed bid to catch her.
The race transformed into the predicted sprint finish and Bronzini won by the narrowest of margins, recording a time of three hours, 21 minutes and 28 seconds.
Neither Cooke nor Armitstead featured prominently at any stage of an encounter defined by tactical caution and the refusal of any national team to show its hand.
"All the teams were racing for a sprint and the circuit is so fast," admitted Cooke.
Mark Cavendish may face similar circumstances as he spearheads Britain's bid for the men's road race world title on Sunday, on a course many - including the 26-year-old Tour de France green jersey winner - believe offers his best chance of winning world gold.
"It all points towards a bunch sprint - if Mark Cavendish could have designed a course, this would be it," said British cycling great and BBC Sport summariser Chris Boardman.
"There is a hell of a lot of pressure for Cavendish, but it is quite clear that this is his best opportunity ever.
"But when one man stands out, it is in the interests of the vast majority of riders not to let him arrive at the line for the bunch finish. No matter how well he plays it, everyone will keep attacking because he's there."