Michael Phelps had set his sights on testing himself against Ryan Lochte on the final day of competition at the Arena Pro Swim Series in Charlotte, North Carolina, on Sunday.
In the end he was not even fast enough to make the same finals as his rival.
The 18-time Olympic gold medalist left the pool frustrated and under no illusions as to the amount of improvement he needs to make for the 2016 Rio Games.
Phelps failed to reach the championship 'A' final in both the 200 meters individual medley and 100 freestyle races on Sunday and came away from the meet without a victory.
"It's just frustrating not setting myself up like I should have," Phelps told reporters. "What I want most is to be racing the competition I need to be racing. I want to race Ryan and those guys. It's frustrating falling short."
Phelps had to settle for winning the 200 IM B final on Sunday. He failed to qualify for the 200 freestyle championship final and finished seventh in the 200 butterfly.