RIO DE JANEIRO — Katie Ledecky’s dominance continued Wednesday night with her anchoring an authoritative American victory in the 800-meter freestyle relay.

Ledecky won her third gold medal and fourth overall medal of the Rio Games, leading relay teammates Allison Schmitt, Leah Smith and Maya DiRado to an easy victory in a time of 7:43:03. Australia was a well-beaten second, despite leading the race by almost a body length when Ledecky started her leg of the relay. Canada captured the bronze medal.

Ledecky’s relay split of 1:53.74 for 200 meters was at least two seconds faster than every other swimmer in the race except for 200 freestyle silver medalist Sarah Sjostrom of Sweden (1:54.88). It was only one-hundredth of a second slower than her gold-medal time in the individual 200 free Tuesday night.

Her tour de force Olympics will conclude later this week with the 800 freestyle, where she is the world-record holder and a prohibitive favorite.

[Related: American Nathan Adrian takes bronze in 100-meter freestyle]

The race also marked the last race for American freestyle star Schmitt. She retires with eight Olympic medals across three Games: four gold, two silver and two bronze.

After Schmitt swam a strong lead-off leg of the semifinals, and with Ledecky and Smith in reserve, the U.S. coaching staff was left with a decision to make about the fourth relay swimmer. The coaches opted to go with DiRado, who already has won two medals here, over struggling 2012 star Missy Franklin and Melanie Margalis. DiRado made the decision look good by swimming a strong third leg and setting up Ledecky for the close-out.

Franklin still has one individual event left, the 200 backstroke.

The victory was America’s third in four relay events in Rio. The lone exception was the women’s 400 freestyle relay, which Ledecky anchored to a silver medal Saturday.