What to watch: Day 4 at the Olympics

Here's a rundown of the key events set to take place on Day 4 of Olympic competition. The events will not be shown live but can be live-streamed on NBC's Olympic website.

Day 4 - Tuesday, July 31, 2012

Jordyn Wieber will attempt to rebound from her disappointing exclusion from the individual all-around competition and lead the U.S. women to their first team gold since the 1996 Olympics, when the "Magnificent Seven" topped the podium in Atlanta.

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In swimming, Michael Phelps will attempt to defend his two-time Olympic title in the 200-meter butterfly final at 2:49 p.m. ET. Phelps is also expected to swim in the 800 freestyle relay at 3:51 p.m. ET. He is two medals shy of breaking the current overall Olympic record of 18 medals, set by Russian gymnast Larisa Latynina. Other swimming finals include the women's 200 free and 200 individual medley. Teen sensation Missy Franklin, who earned her first gold on Monday night, will race in the 200 free.

Fresh off its victory over France, Team USA men's basketball will play Tunisia at 5:15 p.m. ET. Spain will face Australia at 6:15 a.m. ET, and France will tackle Argentina at 3 p.m. ET.

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In tennis, second-round action begins. Serbian Novak Djokovic will face American Andy Roddick at 11 a.m. ET, and Britain's own Andy Murray will take on Finland's Jarkko Nieminen at 9 a.m. ET. In women's singles, Russian Maria Sharapova will battle Great Britain's Laura Robson at 1 p.m. ET, and American Venus Williams will play Canada's Aleksandra Wozniak at 7 a.m. ET as she attempts to win a fourth Olympic gold medal.

And for you whitewater fans, France's Tony Estanguet, Beijing gold medalist Michael Martikan of Slovakia, and British world champion David Florence will battle the rapids in slalom canoeing. The men's single semifinal begins at 8:30 a.m ET, with the final at 10:06 a.m. ET.

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