The Olympic swim star Michael Phelps broke his own American record in the 200-yard butterfly, winning in one minute, 39.65 seconds at the Maryland State Championships at the US Naval Academy.
Phelps set the old mark of 1:39.7 in 2006 at Austin, Texas.
He looked back to see his split times from four years ago and entered the race with a goal of breaking his US mark.
The meet, which took place about 50 kilometres from the home of the 14-time Olympic champion, was the next step in Phelps' training for the 2012 London Olympics after winning an unprecedented eight gold medals in 2008 at Beijing.
Phelps will next take the plunge competitively in a meet at Columbus, Ohio, next month.