Defending champion Alexei Popyrin of Australia beat fifth-seeded Holger Rune of Denmark 4-6, 6-2, 6-3 on Saturday night to reach the National Bank Open quarterfinals.

The Australian has now won seven of his last nine matches against Top 10 players, a stretch that began in Canada a year ago, where—in Montreal—he made a surprise run to his first Masters 1000 title.

TORONTO — Alexei Popyrin remains in the hunt for a second straight National Bank Open crown. The Australian battled back from ...