The match lasted four hours and 26 minutes, surpassing Rafael Nadal’s victory over Novak Djokovic at the Madrid Masters in 2009 as the longest three-set men’s singles match in the Open era.
Federer, who won gold in the men’s doubles with Stanislas Wawrinka in 2008, is now guaranteed at least a silver medal, while Del Potro must recover to battle for bronze on Sunday after leaving Centre Court in tears.
Sharapova in final
Meanwhile, Maria Sharapova will fight for an Olympic gold medal today after beating fellow Russian Maria Kirilenko in the women’s singles semi-finals yesterday.
The third seed, who is playing in her first Games and carried Russia’s flag at the opening ceremony, continued her fine form on the Wimbledon grass this week to win 6-2 6-3.