Kazakhstan's Alexandre Vinokourov will consider retiring after he claimed gold in the men's road race.
The 38-year-old sprinted clear of Colombia's Rigoberto Uran in the final stages to take the win with Norway's Alexander Kristoff finishing third.
"It will be a nice way to finish off my career with a gold medal," he said.
His victory meant disappointment for world champion Mark Cavendish,
who had hoped to win the first gold for Great Britain at London 2012.
Cavendish finished 28th after his GB team-mates failed to reel in a late breakaway in the 250km race that finished on The Mall.
served a two-year ban after testing positive for blood doping in 2007,
will race in the time trial on Wednesday in what could be his final ride.
"After so many crashes returning to cycling was difficult but my family, my children and my parents were behind me all the time," he added.
"I still have a metal plate in my femur so it was not easy and I had not won any stage at the Tour de France but I was still hoping today.
"I will still race in time trial on Wednesday but I have the gold medal I wanted and after that I will consider retiring."