Michael Phelps and Ryan Lochte both safely qualified for the semi-finals of the men's 200 metres individual medley at the London Olympics on Wednesday.
Returning to the pool for the morning heats after they teamed up to win gold for the United States in the 4x200 freestyle relay on Tuesday night, the pair were untroubled making the top 16 for the evening semi-finals.
Phelps, who won the 200 medley at Athens in 2004 and Beijing four years later and is bidding to become the first man to win the same individual event at three Olympics, finished second in his heat and fourth overall despite being fatigued.
"Didn't really get much sleep last night, didn't warm down at all, so this morning didn't feel too comfortable," he said.
Lochte won his heat and was second overall but was conserving his energy because he swam the 200 backstroke heats just before the medley.
"This morning's races were easy. All I had to do was get a lane for tonight and that's what I did," Lochte said.
The fastest overall time was set by Laszlo Cseh of Hungary, who left nothing to chance after missing out on a place on the final for the 400 medley.
South Africa's Chad le Clos was 11th overall. Le Clos upset Phelps in the 200 butterfly final on Tuesday and was so shocked by his victory that he slept with his gold medal.