Bettini held off Paulinho to seal gold in Athens

Italian Bettini edged his Portuguese opponent just metres from the finish line to win the 224.4km event.

They broke away from the main pack with a few laps to go before Bettini justified his position as favourite.

Belgian Axel Merckx, son of five-times Tour de France winner Eddy, made a late surge to grab bronze, with Briton Roger Hammond finishing seventh.

A host of big names had been in contention in the 17-lap race, which wound through central Athens and took the riders under the shadow of the Acropolis, among them Sydney 2000 champion Jan Ullrich and Tyler Hamilton.

But an early crash and the searing heat caused a series of retirements throughout the day.

The biggest casualty from the 153 starters was world cycling champion Igor Astarloa, one of the pre-race favourites.

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Holland's Michael Boogerd, Colombian outsider Marlon Perez and Spaniard Jose Ivan Gutierrez, who were involved in the same crash, also retired.

German Andreas Kloeden, a bronze medallist in Sydney four years ago and second in this year's Tour, failed to finish, as did Russian champion Viatcheslav Ekimov, who will defend his Olympic time trial title next week.

But Italian team leader Bettini held on to seal victory in five hours, 41 minutes, 44 seconds.