Italian Camila Giorgi has now beaten the Australian Open champion in each of their three hardcourt meetings.
Italian Camila Giorgi once again frustrated Caroline Wozniacki on a hard court as she beat the defending champion 6-2, 2-6, 6-4 to reach the quarter-finals of the Pan Pacific Open in Tokyo on Thursday.
Giorgi has now beaten the Australian Open champion in each of their three hardcourt meetings and will next face former world number one Victoria Azarenka for a place in the last four.
Wozniacki is one of the best defensive players on the women's tour but the Dane had no answer to Giorgi's power and accuracy from the baseline, and the Italian sent down 45 winners to wrap up the contest.
After tamely surrendering the first set, Wozniacki roared back to claim the second and go a break up in the decider but Giorgi could not be denied.
The Italian began finding the lines again to break back, and claimed six of the last eight games as she stormed to victory.
"It was a very good match," a poker-faced Giorgi said in an on-court interview. "This is a nice court and (today) was very fun."
Belarusian wildcard Azarenka eased past seventh seed Ashleigh Barty 6-4, 6-2.
Azarenka dominated from the baseline and picked her moments to come to the net to beat the Australian.
Azarenka, who is working her way back up the rankings after a prolonged custody battle over her son, said she is pleased with how she controlled the match.
"I think I played a lot better than in the first round," she said. "I felt I really controlled today and found the court really well.
"Obviously it's been a while since I've played, I'm just trying to look day by day and see what happens. But I'm definitely enjoying my time on court these days."
Czech eighth seed Barbora Strycova fought off Estonian Anett Kontaveit 7-5(5), 3-6, 7-5 in a see-saw battle that lasted just over three hours and will face US Open champion Naomi Osaka for a place in the semi-finals.
Elsewhere, unseeded Croatian Donna Vekic, who shocked fifth seed Sloane Stephens in the first round, beat Briton Johanna Konta 6-3, 7-5 to set up a quarter-final with French second seed Caroline Garcia.
Konta started poorly, but found her feet briefly in the second set, breaking twice to race into a 4-1 lead before imploding with a flurry of unforced errors that allowed Vekic back into the match.