Italian Stefano Baldini won the Olympic men's marathon on Sunday after an intruder dashed on to the course late in the race and bundled the then leader Vanderlei de Lima into the crowd.

De Lima, who surged to the front before the halfway stage of the 42.195 kms race from Marathon to the Panathinaiko stadium, managed to extricate himself from the spectators but was clearly shaken by the incident. The unidentified man, who was dressed in a kilt, was arrested and taken to a police station.

"I lost the gold medal at that moment," de Lima said. "I was afraid, I did not know if the man who attacked was armed."

The twice Pan American champion had been tiring anyway at that stage and Baldini, a former European champion and twice world bronze medallist, slipped into the lead at 40 kms and strode away to a comfortable win in two hours 10 minutes 55 seconds.

American Meb Keflezighi finished second in 2:11:29 with de Lima, who received a standing ovation from the spectators in the venue of the 1896 Athens Games, taking the bronze medal.

The race began in 30 degrees, cooler than the temperatures for last Sunday's women's race but still hot enough for the toughest race on the Olympic athletics programme.

The field remained bunched until 16 kms, when South African Hendrik Ramaala surged into the lead.

Ramaala was overtaken in turn by de Lima who led as the field passed halfway in 67 minutes 33 seconds.

At the 30 kms mark, Lima had extended his lead to 46 seconds, completing the previous five kms in 15:30, the fastest split of the race.

But his margin steadily dwindled as the chasing group, headed by Baldini, drew closer and the clash with the interloper at 37 kms threw him off his stride.

"Today I was sure because I am in top condition," Baldini said. "I was only afraid in the first part because we were too slow.

"The way I ran today made it impossible for anybody to beat me."