Rio Olympics Day 9: What to watch

Andy Murray defends his tennis title, men's and women's individual gymnastics medals are awarded, and Usain Bolt goes for a three-peat. 

Day 8 of the Rio Olympics was a historic one: It marked the end of a long and successful career for Michael Phelps, the swimmer with a record-breaking 23 medals, as he swam to victory in his final event, the 4x100-meter medley relay. The US became the first nation to win 1,000 Olympic gold medals. Russia's only athletics competitor, long jumper Darya Klishina, was suspended by the International Association of Athletics Federations. And, in an upset victory, Puerto Rico won its first Olympic gold medal when tennis player Monica Puig defeated world No. 2 Angelique Kerber of Germany in the women's singles final. 

Sunday promises to be just as eventful, as Usain Bolt defends his 100m Olympic title, gymnasts compete in individual final events, and reigning tennis champ Andy Murray goes up against Juan Martín del Potro. 

Here are a few highlights. You can watch the Olympics on NBC-TV or online through live streaming. All events are in Eastern time. 

Track and field: Defending champion Mr. Bolt of Jamaica will go up against Justin Gatlin, the 2004 champ from the United States, in the men's 100 meter final. If he wins, Bolt will win his third straight gold medal, becoming the first athlete to three-peat in the event. Catch the race at 9:25 p.m.

Tennis: Mr. Murray will defend his Olympic title against Argentina's Mr. del Potro, the 2012 bronze medalist. Del Potro beat No. 1 Novak Đoković of Serbia in a surprising victory in the first round, then went on to defeat 2008 champion Rafael Nadal in the semifinals. The match starts at 3 p.m. You can also watch the bronze medal match, between Mr. Nadal and Japan's Kei Nishikori, at 1 p.m, and the women's doubles finals at 11 a.m.

Gymnastics: Both men and women will compete in four individual event finals, with men on the floor and pommel horse and women on the vault and uneven bars. American teenager Simone Biles, a three-time world all-around champion, is the favorite for vault. Fellow Americans Gabby Douglas and Madison Kocian are expected to shine on the uneven bars. Japan's Kenzo Shirai and Kohei Uchimura are favorites on the men's floor. The events begin at 1 p.m.