Belgium's Philippe Gilbert won the men's road race at the UCI Road World Championships after breaking away on the final climb of the Cauberg hill in Limberg.
The 30-year-old left rivals Edvald Boasson Hagen of Norway and Spain's Alejandro Valverde in his wake towards the end of the 267-kilometre race through the Netherlands.
The Belgian team had faced an early challenge from both recent Vuelta a Espana winner Alberto Contador and France's Thomas Voeckler, but Gilbert managed to break away on the final climb. British rider Mark Cavendish was unable to defend his title after retiring with 111km of the race remaining.
The 27-year-old sprinter had already admitted the hilly terrain was ill-suited to his personal style, in contrast to the flat roads of Copenhagen where he raced to glory last year.
Cavendish's Team Sky colleagues and Olympic medallists Bradley Wiggins and Chris Froome also dropped out of the arduous race before reaching the final stages.
A triumphant Gilbert told limburg2012.nl: "I went on the steepest part of the Cauberg and totally focused on my effort. I really enjoyed all the fans and knew my family and friends are here. A fantastic feeling.
"It's hard to realise I'm the world champion. I'll be wearing the jersey for the first time in Piemonte, that's going to be a great moment. My form was good after the Tour de France where I worked for my team-mates. I built up towards the Olympics and found real strength in the Vuelta. So that gave me confidence."
Silver medallist Boasson Hagen, 25, added: "This is the best I could do so I'm satisfied. The course was less difficult then expected because of the wind on our backs."
Earlier, Matej Mohoric of Slovenia claimed the men's world junior title after stunning Australia's Caleb Ewan with a sprint on the final kilometre.