RIO DE JANEIRO (AP) — Sun Yang of China won't be defending his Olympic title in the men's 1,500-meter freestyle.

Sun finished 16th in Friday's preliminaries and only the top eight advanced to the final on Saturday, the last day of swimming at the Rio Olympics.

Gregorio Paltrinieri of Italy had the fastest time of 14 minutes, 44.51 seconds. He won the world title last year when Sun failed to appear on the blocks for the start of the grueling race.

Sun heard rumors that he wouldn't compete Friday, but he showed up and was clocked in 15:01.97.

"I actually think even if I finished in 16 or 17 minutes, as long as I did it, that would be encouragement for myself," he said through a translator.

Sun said he had been sick after winning the 200 free on Monday and also hasn't swum the 1,500 often in the last few years.

Connor Jaeger of the United States was second in 14:45.74. American Jordan Wilimovsky, who also qualified in open water swimming, was third at 14:48.47.

Mack Horton of Australia was fourth. He called Sun "a drug cheat'" after beating the Chinese to win the 400 free.

"It really doesn't matter if he is there or not,'" Horton said of Sun missing out.

Another former 1,500 champion also failed to advance. Ous Mellouli of Tunisia, who won at the 2008 Beijing Olympics, finished 21st. He will compete in the 10-kilometer open water race next week at Copacabana Beach.

"This is the Olympics of upsets,'" Wilimovsky said.

A day after becoming the first African American woman to win an individual Olympic gold, Simone Manuel of the United States was back in the pool for the 50 free. She was all business in advancing out of the preliminaries with the 11th-fastest time of 24.71 seconds.

Pernille Blume of Denmark was the top qualifier in 24.23. Also reaching the semifinals were sisters Cate and Bronte Campbell of Australia, defending Olympic champion Ranomi Kromowidjojo of the Netherlands, American Abbey Weitzeil, and 39-year-old Therese Alshammar of Sweden.

Manuel shared the 100 free title with 16-year-old Canadian Penny Oleksiak, who didn't enter the shorter sprint.

China's Chen Xinyi withdrew after testing positive for a banned substance.

Britain topped the qualifying heats for the men's 4x100 medley relay. Chris Walker-Hebborn, Adam Peaty, James Guy and Duncan Scott were clocked in 3 minutes, 30.47 seconds.

The U.S. team of David Plummer, Kevin Cordes, Tom Shields and Caeleb Dressel were second fastest in 3:31.83. Michael Phelps will join the team for the final on Saturday in the last race of his record-setting career.

Also moving into the final was host country Brazil, ensuring fans at the Olympic Aquatics Center will be cheering loudly.

The United States blew away the field in the women's 4x100 medley relay heats.

Olivia Smoliga, Katie Meili, Kelci Worrell and Abbey Weitzeil qualified fastest in 3:54.67 — 2.13 seconds ahead of second-place Canada. In the final on Saturday, Manuel is expected to be part of the U.S. team.

The Canadians were timed in 3:56.80, followed by Denmark in 3:56.98.