Ashleigh Barty has sent 16th-seeded Russian Elena Vesnina crashing out of the Rogers Cup in Toronto.
Barty, ranked 58th in the WTA standings, beat world No.18 Vesnina 6-3 5-7 6-4 in a match that lasted just over two hours.
The 21-year-old Queenslander, who came through qualifying to take her place in the main draw, sent down nine aces but had to overcome 12 double faults to progress to the last 16.
Barty will now face Wimbledon champion Garbine Muguruza for a place in the quarter-finals.
Muguruza tamed Kirsten Flipkens 7-5 6-2 on a blockbuster day that sees eight of the world's top 10 in action.
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The Spanish world No.4, led the day-long parade of top seeds onto court and needed 85 minutes to dispatch the Belgian qualifier before turning the stadium over to newly-minted Czech world No.1 Karolina Pliskova who made similarly light work of Anastasia Pavlyuchenkova.
Despite an unthreatening world ranking of 82, Flipkens represented a tricky first test for Muguruza with the Spaniard holding only a slight 3-2 edge in their head-to-head meetings.
Both players were making their third appearance at the Canadian event with Flipkens having found more success after advancing to the third round in 2013. Muguruza had managed just one match win in her two previous visits.
"It (first set) was tough, Kirsten is such a talented player... I'm very happy that I finally did it," Muguruza said.
"I tried to reduce the mistakes I made in the first set and I was a little more lucky there, I just wanted it so much."
American teenager Catherine Bellis continued her brilliant form on the North American hardcourts by taking down eighth-seeded Russian Svetlana Kuznetsova 6-4 7-5 to reach the third round.
The 18-year-old arrived in Toronto after reaching the semi-finals last week at Stanford.
Lucie Safarova of the Czech Republic beat Slovakian 11th seed Dominika Cibulkova 6-2 6-4.
