Poland's Tomasz Majewski has become the first man in almost 60 years to retain the Olympic shot put title.
He produced a throw of 21.87m in round three to take the lead from world champion David Storl of Germany, who managed 21.86 in round two.
With the title already won, Majewski, 30, then threw 21.89 in the final round - his best throw of the season.
American Reece Hoffa threw 21.23 to beat his compatriot Christian Cantwell (21.19) to bronze.
Majewski's victory saw him emulate American Parry O'Brien, who won successive shot put titles in 1952 and 1956.
Afterwards Majewski predicted that Storl would be shot put Olympic champion at the next Games.
He said: "He is young, he is explosive and will always throw very far. The next Olympic Games will be his, but this one is mine."
For Hoffa, just finally winning an Olympic medal was reward enough.
The American said: "I cannot tell you how hard it was to finally get a medal. To get a medal in London is awesome - and this might be my last Olympic Games.
"It was incredibly tough and I am happy I got a medal, the experience here in London is incredible."
Britain's Carl Myerscough failed to reach the final after finishing 29th in qualifying with a throw of 18.95m - more than a metre down on his season's best.
Myerscough, who served a two-year ban for testing positive for anabolic steroids in 1999, was allowed to compete in London when the British Olympic Association's lifetime ban for drug cheats was overturned.
Watch how Majewski won shot put gold.