Hungary’s Kristof Milak broke his own 200m butterfly world record as he retained his world title in front of a delirious Duna Arena crowd in Budapest.
The 22-year-old Olympic champion was always ahead of schedule as he left his rivals behind and chased the record he set back in July 2019.
His time of one minute 50.34 seconds lowered the world mark by 0.39 seconds.
“This is my home, the pool belongs to me, lane four belongs to me,” he said afterwards.
“I have 4,000 amazing people here to watch me and I couldn’t let them down.”
Britain’s James Guy went off hard and was second at the turn, but ran out of steam as France’s Leon Marchand finished second, more than three seconds off Milak, and Tomoru Honda of Japan took third.
Great Britain’s Freya Anderson was fastest into the 200m freestyle final, but finished down in fourth as China’s Yang Junxuan took world gold.
Anderson turned for home in sixth position and finished fast, but was still well off third-placed Chinese Tang Muhan.
Anderson finished fourth for a second time as she anchored home the British team, completed by Guy, James Wilby and Medi Harris, in a 4x100m medley relay won by the United States.
American Bobby Finke won the men’s 800m freestyle with an electric late burst to finish ahead of Germany’s Florian Wellbrock and Ukrainian Mykhailo Romanchuk.
Finke’s surge mirrored the tactics that delivered the 22-year-old Olympic gold in the same event in the summer.
“I knew I just had to just stick with them and stay with what I am good at, the finish. I knew the 50 length was going to hurt but it was worth it,” said Finke.
Wednesday’s crowd will be denied the eagerly-awaited meeting between American Olympic and world champion Caeleb Dressel and Romanian 17-year-old prodigy David Popovici after Dressel withdrew from the 100m freestyle semi-finals with a medical issue.
Popovici won Monday’s 200m freestyle final by more than a second in a dominant display.
“The team will determine his participation in the events later in the week,” added a United States team statement on Dressel.