Caeleb Dressel of the United States won his third gold medal of these Olympics, setting a world record in the 100-meter butterfly with a time of 49.45 seconds.

Dressel already held the world record (49.5 seconds, in 2019) and the Olympic record (49.71, Friday), and he came to the final as the favorite. No one else in the field went below 50 seconds in their preliminary heats.

Kristof Milak of Hungary, the gold medalist in the 200 fly, swam to Dressel’s left, and Dressel suspected that is where his closest competition would be. The two of them, and Michael Phelps and Milorad Cavic, were the only ones to swim sub-50 seconds in this event’s history.

Within an hour of swimming the 100 fly, Dressel will compete in a semifinal heat of the 50 free. That final is Sunday morning in Tokyo (Saturday night Eastern time).