Yuriy Bilonog of the Ukraine edged out American Adam Nelson with his final throw to take the Olympic men's shot put gold medal.
Bilonog left it late to claim gold
Nelson threw 21.16m in the first round and led until Bilonog equalled that mark with his sixth and last attempt.
The Ukrainian was declared the winner because of his second-best effort of 21.15m - Nelson had fouled on all five of his other throws.
Joachim Olsen of Denmark won the bronze medal with a throw of 21.07m
Irina Korzhanenko won the women's shot put, the first athletics gold of the Games.
The Russian threw 21.06 metres - almost a metre and a half clear of silver medalist Yumileidi Cumba of Cuba with German Nadine Kleinert taking bronze.
European champion Korzhanenko, who was disqualified from the 1999 World Indoor Championships for a doping offence, had managed the second leading throw of the morning qualifiers with 19.43.
Both the men's and women's event was held in Olympia, around 320 km south west of Athens.