Juan Martín del Potro of Argentina ended Rafael Nadal’s hopes of a second Olympic singles title with a 5-7, 6-4, 7-6 (5) victory to set up a gold medal showdown with the defending champion, Andy Murray of Britain.
Del Potro, whose career was almost ended by a series of wrist operations, prevailed after 3 hours 8 minutes.
The second-seeded Murray reached his second successive Olympic final with a 6-1, 6-4 victory over Japan’s Kei Nishikori.
The Spaniard Nadal, the 2008 singles champion, had won the men’s doubles on Friday with Marc Lopez, but playing his 10th match of the Rio tournament finally caught up with him.