American swimmer Ryan Murphy won gold while his teammate David Plummer won bronze in the men's 100-meter backstroke in Rio on Monday night.
Xu Jiayu of China came in second to win the silver medal.
The performance continued a dominant run in event for the U.S. at the Olympics. The U.S. has not lost the event since Canadian Mark Tewksbury narrowly beat Jeff Rouse for the gold at the 1992 Olympics in Barcelona.
Plummer and Murphy, both swimming in their first Olympics, came into the event ranked Nos. 1 and 2 in the world.
While they posted only the fourth and fifth best times in the preliminary heats, they topped the semifinals to advance Sunday night, with Murphy finishing in 52.49 and Plummer just 0.01 seconds behind him.
Murphy, 21, who swims collegiately for Cal, will also be competing in the 200-meter backstroke on Wednesday and Thursday and will be part of the U.S. team defending its 2012 Olympic gold in the 4x100-meter medley relay starting Friday.
Plummer, a 30-year-old Oklahoma native who swam collegiately at the University of Minnesota, will be joining Murphy on that relay team.