USA's Errol Spence fights Brazil's Myke Ribeiro de Carvalho during their men's welter 69-kg boxing match at the 2012 Summer Olympics, Sunday, July 29, 2012, in London. (AP Photo/Ivan Sekretarev)

LONDON (AP) -- The U.S. men's boxing team is heading home with no Olympic medals for the first time.

Welterweight Errol Spence dropped a 16-11 decision to Russia's Andrey Zamkovoy in the quarterfinals on Tuesday night.

Spence represented the last chance for the most successful team in Olympic boxing history to add to its record 108 medals. Instead, the Dallas-area fighter started slowly and never got going in his team's ninth loss in 10 fights.

Spence only reached the quarterfinals after the Americans successfully protested a loss to India's Krishan Vikas.

Welterweight Freddie Evans clinched Britain's fifth medal of the Olympic tournament with a tiebreaker victory over Custio Clayton, who fell just short of Canada's first boxing medal since 1996.