All of the USA swimmers advanced out of morning preliminaries on Sunday to the night session.
Team USA’s Kathleen Baker kicked things off, posting a personal best to clock the fastest time of the morning’s 100m backstroke preliminary heats, 58.84 seconds. Reigning world champion, Emily Seebohm of Australia, qualified for the semifinal second with 58.99 seconds.
Also into the semifinals are the U.S.’ Olivia Smoliga (sixth with 59.60) and Hungary’s Katinka Hosszu, who posted 59.13 seconds the morning after winning the 400m individual medley gold in world record time.
13-year-old Gaurika Singh, representing Nepal and the youngest athlete in the Olympics, won her backstroke heat in a time of 1:09.45. Reigning Olympic champion, Missy Franklin, missed out on qualifying for this event at the U.S. Trials in June.
Both Americans in the 200m freestyle field advanced to Sunday evening’s 16-man semifinals: Conor Dwyer won his heat in 1:45.95 and Townley Haas placed second in his heat to Germany’s Paul Biedermann, who holds the event’s world record.
The top qualifier was China’s Sun Yang, who tied for silver at the 2012 Olympics in the 200m freestyle. Sun touched out South Africa’s Chad le Clos in their heat, though le Clos safely advanced to the semifinal, too.
2012 Olympic gold and co-silver medalists, Yannick Agnel of France and Park Tae Hwan of South Korea, missed the 16-man final.
The U.S.’ Olympic rookies, Katie Meili and Lilly King, each won their 100m breaststroke heats. Meili clocked 1:06.00; King raced to 1:05.78, beating defending Olympic champion Ruta Meilutyte of Lithuania to posted 1:06.35. All three times were good enough to advance to the semifinal on Sunday night.
Yulia Efimova, who’s entry in the 2016 Olympics were subject to change up to the last minute due to a Russian doping scandal and her own positive doping tests, won her heat with a time of 1:05.79.
Americans Ryan Murphy and David Plummer – both competing at their first Games – qualified fourth and fifth into the 100m backstroke semifinal. Murphy touched second in his heat with a time of 53.06, while Plummer won his heat with 53.19.
World champion Mitch Larkin of Australia, finished second to France’s Camille Lacourt by less than a tenth of a second.
Reigning Olympic champion Matt Grevers did not qualify for the 2016 Rio Olympics at the U.S. Trials in June.
Team USA swimmer Katie Ledecky, who already owns a silver medal from these Games, broke the 400m freestyle Olympic record in the preliminary heat. She raced to 3:58.71, the only woman in the field under the four-minute barrier.
Her world record, set in August 2014, stands at 3:58.37.
Joining Ledecky in the eight-woman final will be teammate Leah Smith, who raced to 4:03.39.
In distances 400m and longer, there is no semifinal and the top eight swimmers advance directly to the final from the preliminary heats.
Anchoring the U.S.’ 4x100m freestyle relay, 35-year-old Anthony Ervin held off a charging Australian squad. Jimmy Feigen, Ryan Held, Blake Pieroni and Ervin raced to 3:12.38, compared to Australia’s 3.12.65.
But it was the Russian quartet, swimming in the prior heat, who posted the fastest relay time of the preliminaries: 3:12.04. All teams are medal favorites, and advanced directly to Sunday night’s final.