Phelps tops 100m fly qualifying in return
Michael Phelps warms up in the practice pool during day one of the Arena Grand Prix at the Skyline Aquatic Center on April 24, 2014 in Mesa, Arizona - by Christian Petersen
Phelps, competing for the first time since the 2012 London Olympics, won his heat in the morning's best time of 52.84sec to launch a comeback that could take him to the 2016 Rio Olympics.
Ryan Lochte, swimming in the heat ahead of Phelps, clocked the morning's second-fastest time of 52.94.
It was a smooth return for Phelps, whose 18 Olympic gold medals include the unprecedented eight he won in eight events at the 2008 Beijing Games.
A cheer went up and cellphone cameras clicked as Phelps mounted the starting block. He delivered his trademark armswing prior to the start and then he was off.
Phelps, 28, says he's a swimming "grandfather" now, but the chance to see him swim has already galvanized the sport's fans.
Tickets to all sessions at the 1,200-seat Skyline Aquatic Center in suburban Phoenix were sold out the day after Phelps announced on April 14 that he would return -- compared to one sold-out session for the Saturday night finals last year.
"Not typical," a USA Swimming spokesman said as he glanced at the stands packed for Thursday's heats, and a throng of fans snapped pictures as he headed to the warm-up pool.
The 100 media credentials issued were five times as many as last year for the meeting, which is the fourth of six events in the Grand Prix series sponsored by suitmaker Arena.
Phelps himself knows just how long a road it is to Rio, and is downplaying 2016 as his ultimate goal.
But his time on Thursday put him comfortably inside the qualifying time of 54.79sec required to make the US championships in August, where he'll have to swim to qualify for the 2014 Pan Pacific Championships and 2015 World Championships in Russia.