Third seed Angelique Kerber has surprisingly lost to America’s Sloane Stephens in the Rogers Cup ladies event in Toronto, Canada.
The former world number 11 defeated Germany’s Kerber 6-2 6-2 in 58 minutes to reach the quarter-final and now faces Lucie Safarova who beat Russia’s Ekaterina Makarova 6-3 6-7 6-2.
In other round of 16 games, new world number one Karolina Pliskova survived a scare to reach the quarter-finals as Japanese teenager Naomi Osaka retired.
Osaka, 19, ranked 50th in the world leveled the scores after winning the second set 7-6 but called for a trainer and retired while Pliskova was leading the third set 1-0.
Pliskova advanced through in a set of 6-2 6-7 1-0 and will meet former world number one Caroline Wozniacki in the last eight who swept past 10th-seeded Polish Agnieszka Radwanska 6-3 6-1 in only 78 minutes.
Defending champion Simona Halep, eased through to the quarters with a 6-1 6-0 demolition of the 26th-ranked Barbora Strycova, while France’s Caroline Garcia beat 18-year-old American Catherine Bellis 6-4 6-2.
Ukraine’s Elina Svitolina comfortably defeated American Venus Williams 6-2 6-1, setting up a meeting with Spain’s Wimbledon champion Garbine Muguruza, who beat Ashleigh Barty of Australia 6-0 3-6 6-2.