(CNN) -- A tennis rivalry is revisited and the world's fastest men compete for gold. Here are five things to look for Sunday at the 2012 London Games:
1) Tennis: Federer and Murray square off on Centre Court
Wait. Didn't these two just play?
World No. 1 Roger Federer faces hometown favorite Andy Murray, whom he defeated at Wimbledon last month.
Federer, who has 17 grand slam titles under his belt, is hoping to complete a career golden grand slam. Only Andre Agassi and Rafael Nadal have achieved the feat of claiming a full set of grand slam titles and backed it it with Olympic gold in the singles.
The gold medal match is scheduled to get under way around 2 p.m. London time (9 a.m. ET).
2) Track and Field: Men's 100-meter showdown
Don't blink. You might miss the men's 100-meter final.
Jamaican sprinter Usain Bolt could become the first sprinter since U.S. Olympic legend Carl Lewis to defend an Olympic 100-meter title. Bolt smashed the world record in Beijing with a time of 9.69 seconds.
But this year, teammates Yohan Blake and Asafa Powell are hot on his heels, as are members of Team USA. Justin Gatlin and Ryan Bailey have both posted sub-10-second times.
The final is scheduled for 9:50 p.m. (4:50 p.m. ET).
3) Track and Field: A slower burn
On the women's side, runners will compete in what is the longest race at the Olympics. Gunning for gold in the marathon are favorites Mary Keitany, from Kenya, and Liliya Shobukhova, from Russia. Both have personal bests at under 2:18:40.
Noticeably absent from the race will be world record holder Paula Radcliffe, from Great Britain, who withdrew citing a recent injury.
"However hard today is, finally closing the door on that dream, at least I can know that I truly have tried absolutely everything," she said last month, according to United Kingdom Athletics. A recent foot injury was too much to overcome, said the 38-year-old.
U.S. marathoner Desiree Davila also dropped out with a leg injury.
The women's race is scheduled to kick off at 11:00 a.m. (6 a.m. ET).
4) Gymnastics: Floor, pommel horse and vault
After a two-day break, gymnastics competition is set to resume for both the men and women.
The men will take to the arena first to compete in the floor exercise. Japan's Kohei Uchimura, who took gold in the men's individual all-around final last week, will face Kai Zou, from China, and Jacob Dalton, from the United States, among others. Men will also compete on the pommel horse.
On the women's side, U.S. gymnast McKayla Maroney looks like a favorite to take the vault. She helped the U.S. women's gymnastics team win its second gold medal ever last week. The team had the highest score in three of the four events, including the vault, which it did first. Maroney scored a meet-high 16.233 to lead the Americans.
The day's competitions begin with the men's flood exercise at 2 p.m. (9 a.m. ET)
5) Diving: All eyes on Wu
China's Wu Minxia is competing for her sixth Olympic medal. If she wins, she would tie the record number of Olympic diving medals, currently held by Wu's former synchro partner and fellow Chinese star, Guo Jinging. Wu has already won gold this year in London, with He Zi, in the women's synchronized 3-meter springboard.
The competition is scheduled to start at 2:30 p.m. (9:30 a.m. ET).