Men's 50-Meter Freestyle
Such a fast race, the 50-meter freestyle leaves little room for error -- even in the preliminary rounds. If he intends on defending his Olympic title, Cesar Cielo will need an even stronger race in the semifinals.
Trinidad and Tobago's George Richard Bovell had the fastest swim of the heats with a time of 21.77. Cielo took second with a time of 21.80.
The U.S.' Anthony Ervin (4th, 21.83) and Cullen Jones (6th, 21.95) also qualified, as well as Australia's James Magnussen (10th, 22.11).
Ervin is an interesting story, returning to his first Olympic games since 2000 where he and Gary Hall Jr. tied for the gold medal in the 50 free. Magnussen, meanwhile, is looking to salvage his Olympics and the 50 free could be his last chance for an individual medal.
Women's 800-Meter Freestyle
Katie Ledecky had to wait six days to finally hit the pool. But when she did, it was worth the wait.
The 15-year-old Ledecky, Team USA's youngest swimmer, finished with the third best time of the morning (8:23.84) and will be one to watch in the finals tomorrow at 2:45pm ET. The favorite still is Great Britain's Becky Adlington, who holds the world record in the event and finished first in the heats with a time of 8:21.78.
Men's 100-Meter Butterfly
Michael Phelps went from last in the first 50 meters to winning his heat. Such a typical way for the most decorated Olympian ever to swim his last-ever Olympic heat.
Phelps (51.72) finished second in the heats to South Africa's Chad le Clos (51.54), the man who remarkably out-touched Phelps for gold in the 200 fly. Also advancing were Milorad Cavic and Phelps' teammate Tyler McGill.
Women's 200-Meter Backstroke
In the morning heats, Missy Franklin (2:07.54) and Elizabeth Beisel (2:07.82) finished first and second, respectively. Franklin looks poised to vie for her third gold medal in one of her specialty events.
South African Olympic veteran Kirsty Coventry also advanced with a third-place finish.