Here are the biggest storylines to watch for Saturday at the Rio Olympics.
Michael Phelps' final race
Phelps will finish his record-setting Rio Olympics with the men's 4x100-meter medley relay. The most decorated Olympian of all time can add to his total of 27 medals as the USA qualified second behind Britain. Despite comments by Ryan Lochte saying Phelps will be back in four years, Phelps has said this is it.
Bolt begins his Games
In the men’s 100, Usain Bolt takes his first steps in these Games in the preliminary heats (11 a.m. ET). Justin Gatlin, Trayvon Bromell and Marvin Bracy are the American challengers. The women’s 100 semifinals and final are this event. The USA would like to have three in the final (English Gardner, Tori Bowie, Tianna Bartoletta) where they will face two-time defending champ Shelly-Ann Frayser-Pryce and Elaine Thompson of Jamaica and Dafne Schippers of Netherlands. Galen Rupp will try to repeat his silver medal from London. Britain’s Mo Farah, Rupp’s training partner, will aim to defend his gold (8:27 p.m. ET). And in the men’s long jump, Jeff Henderson and Jarrion Lawson will try to win a gold medal for the USA for the first time since 2004.
More fencing medals up for grabs
In the women's team sabre competition, the Americans are medal contenders with No. 1 Mariel Zagunis leading the team. Also in the lineup is Ibtihaj Muhammad, the first American to compete in the Games wearing a hijab.
Rowing dominance on the line
In the women's eight, the Americans look to add to their historic run. The U.S. women’s eight has won 10 consecutive titles in the world championships and Olympics, a mind-boggling streak that is almost unmatched in any sport.
Tennis semifinals
Venus Williams teams up with Rajeev Ram in the semifinals of the mixed doubles competition. They will play Sania Mirza and Rohan Bopanna of India. In the other semifinal, Jack Sock and Bethanie Mattek-Sands face Lucie Hradecka and Radek Stepanek of the Czech Republic.
