(REUTERS) - Swimming legend Michael Phelps continued his comeback from retirement with a tie for victory and a second-place finish at a US Grand Prix Series meet in Santa Clara, California on Friday.

While certainly not back to his dominant best since hanging up his goggles following the 2012 London Olympics, he tied for first in the 100 metres butterfly with Tom Shields but had to settle for second behind Nathan Adrian in the 100m freestyle.

In his third meet since taking nearly two years off from the sport, the 28-year-old Phelps competed in multiple finals in the same session for the first time on his return to competitive swimming.

The most decorated Olympian of all-time (22 medals, 18 gold) matched Shields in 52.11sec to share top spot in the butterfly, finishing the faster of the two but unable to edge his way in front.

The pair's time was the joint-second fastest by an American this year behind Ryan Lochte.

Earlier, Phelps clocked 48.80sec in the 100m freestyle, beaten easily by Olympic champion Adrian, who touched the wall in 48.17.

He is scheduled to swim the 200m freestyle on Saturday and the 200m individual medley on Sunday.

The women's headliner of the meet, Missy Franklin, finished second in the 100m freestyle behind Simone Manuel.