For the second straight day at the National Collegiate Athletic Association (NCAA) Division I Swimming and Diving Championships in Minneapolis, Olympic champion Joseph Schooling was upstaged by his arch-rival Caeleb Dressel.
The 22-year-old Singaporean finished fourth in his pet 100-yard butterfly early yesterday morning (Singapore time), despite winning the event in 2015 and 2016.
He clocked 44.68sec while Dressel set an NCAA record en route to winning in 42.80 - the first time anyone had posted a sub-43 swim.
Dressel, 21, held the previous record of 43.58, set last year when he won the same race. Schooling was second then in 43.75, which was his personal best.
This time, the University of Texas senior did not get onto the podium. Dressel's University of Florida team-mate Jan Switkowski (44.49) ensured a one-two finish for the Gators, just ahead of Indiana University's Vini Lanza (44.50).
Speaking after his race in a video posted on leading swimming website Swimswam, Dressel, who won seven golds at last year's World Championships, said he could not explain his blistering form.
He added: "I wish I had answers. That's a good quote I've learnt over the years, I don't know. I just try to listen and do what I'm told, listen to my coaches. I've got fantastic coaches and a fantastic environment at Florida."
There was no joy for Texas in the 200-yard medley relay either, as the defending champions finished fifth (1:23.21), fielding Schooling (23.69) in the breaststroke leg in the absence of a true specialist this year after Will Licon graduated.
The race was won by the University of Southern California quartet (1:21.82) of Robert Glinta, Carsten Vissering, Dylan Carter and Santo Condorelli, although Dressel once again hogged the headlines thanks to his freestyle split of 17.37 for Florida, faster than the 17.63 clocked to win the 50-yard free on Friday.
Indiana hold the lead in the team rankings with 325 points, followed by Texas(306) and the University of California at Berkeley (291.5 points). Texas have won three straight NCAA Championships under head coach Eddie Reese.
Dressel said: "Indiana and Texas look really good. We probably need a miracle even to come close to first, so at this point, just have fun."
The NCAAs end today with Schooling swimming in the 200-yard fly in which he faces compatriot Quah Zheng Wen, and the 400-yard freestyle relay.