Litherland wins Pro Swim 400 IM as Marchand disqualified
The 19-year-old, who trains at Arizona State University under retired great Michael Phelps's longtime coach Bob Bowman, touched first with a time flashing up of a world-leading 4min 10.38sec, but he was disqualified for an improper turn on the final freestyle leg and American Jay Litherland scooped the victory in 4:19.63.
Despite the disappointing outcome, Marchand stamped himself someone to watch ahead of the World Championships in Budapest June 18-23.
In other events on Thursday, US superstar Katie Ledecky continued her preparation for the United States' World Championship trials with a victory in the 200m freestyle in 1:55.66.
It wasn't her fastest of the season but Ledecky, the seven-time Olympic gold medallist who has moved from California to Florida to train with Anthony Nesty, said it was satisfactory for this point in the season.
"I thought it was pretty good," Ledecky said. "It hurt a little more than I was hoping it would, but I was working through it and the time was solid."
US Olympic gold medallist Lilly King won the 100m breaststroke in 1:05.32, edging Anna Elendt whose 1:05.58 lowered the German national record she had set in the heats of 1:05.96.
American Shaine Casas won the men's 100m butterfly in 51.09sec as Olympic gold medallist and world record-holder Caeleb Dressel settled for second in 51.79.
Coleman Stewart was third in 51.93.