Hubert Kos powered to gold in the men's 200m backstroke on Thursday, touching in 1min 54.26sec to deliver Hungary's first gold of the Paris Olympics.
Greece's Apostolos Christou, who had led until the final turn, took the silver medal, finishing 0.56sec behind Kos, while Switzerland's Roman Mityukov won bronze.
Kos came into the race as the favourite but had plenty of work to do on the final lap after Christou's impressive showing.
The 2023 world champion, who is trained by Michael Phelps's former coach Bob Bowman, produced a devastating final 25 metres to leave the Greek in his wake and finish a comfortable winner in the end.
It continues an impressive Olympics for Bowman's swimmers, with French favourite Leon Marchand having already claimed three gold medals.
Kos, who swims at Arizona State University, is the first Hungarian to win the event since Sandor Wladar in Moscow in 1980.