Phelps strong in 100m fly qualifying
Michael Phelps reacts to applause after winning his heat in the men's 100 meter butterfly prelims during the 2014 Phillips 66 National Championships at the Woollett Aquatic Center on August 8, 2014 in Irvine, California - by Harry How
Phelps won his heat in 51.17sec -- faster than the previous season-best of 51.29 set by South African Chad Le Clos at the Commonwealth Games.
Tim Phillips won his heat in the morning's second-quickest time of 51.49, with Tom Shields third-fastest in 51.55.
Matt Ellis won his heat in 51.77 and Ryan Lochte, swimming next to Phelps, had the fifth-fastest qualifying time of 51.91.
"As soon as Ryan and I saw those guys going 51 we were like 'What is this? Can we just have an easy morning?'" Phelps said.
In fact, the 18-time Olympic gold medalist was delighted to grab the top time of the season -- something he'd hoped to do at a meet in Atlanta in July.
The 29-year-old is swimming just his fourth meet since ending a near two-year retirement in April.
He has a chance to take his comeback to another level by booking a spot in his first major international competition since the London Games with the nationals serving as the qualifying meeting for the Pan Pacific Championships in Gold Coast, Australia, August 21-25.
Results from this week and the PanPacs will determine the US team for the 2015 World Championships in Russia.
Phelps' first event of the week had gone badly, as he mis-judged the turn in the 100m free on Wednesday and finished seventh.