MELBOURNE, Jan 26 — Jessica Pegula knocked out defending champion Madison Keys at the Australian Open today as the American sixth seed secured a dominant 6-3 6-4 victory to reach the quarter-finals at Melbourne Park for the fourth time.

Facing a close friend with whom she hosts “The Player’s Box” podcast, Pegula made a blistering start at Rod Laver Arena and only briefly let the momentum slip early in the match to remain on course for a first major title.