Dominika Cibulkova of Slovakia eliminated eighth-seeded Angelique Kerber of Germany in second-round play Tuesday at the Rogers Cup women's tennis tournament.
The unseeded Cibulkova, ranked No. 20 in the world, needed almost three hours to complete the 6-7 (0), 6-2, 7-5 victory at Rexall Centre at York University.
"It was a really tough match," Cibulkova said. "Angelique, she was putting everything back. Her defensive game is really good and I just had to be patient and aggressive today.
"So it was not easy. My serve was not working like I was expecting but in the end I made it, so I was really happy."
No. 11 seed Maria Kirilenko of Russia and 16th-seeded Serb Ana Ivanovic won their first-round matches in straight sets. Kirilenko beat qualifier Petra Martic of Croatia 6-2, 6-1 while Ivanovic defeated Su-Wei Hsieh of Taiwan 6-1, 6-2.
"It's good to be back here," Ivanovic said. "I'm really looking forward to consistency and especially coming off how I played well last week.
"I hope (to) keep that momentum going and to keep playing well here."
Ivanovic reached the semifinal at the Southern California Open last weekend before losing to Victoria Azarenka of Belarus.
In other first-round matches, Toronto's Sharon Fichman beat Stephanie Dubois of Laval, Que., 5-7, 6-2, 6-2 and No. 13 seed Kirsten Flipkens of Belgium defeated American Venus Williams 0-6, 6-4, 6-2.
"I wasn't really expecting to play that well in the first set," Williams said. "So I think that in the second, I just kind of didn't handle it well. But I was pretty close there to closing that match out and then got down in the third."
No. 15 seed Jelena Jankovic of Serbia topped Georgian qualifier Anna Tatishvili 7-6 (6), 4-6, 6-3, Ekaterina Makarova of Russia beat Anastasia Rodionova of Australia 6-1, 7-5 and American qualifier Lauren Davis edged Svetlana Kuznetsova 3-6, 7-5, 7-5.
France's Alize Cornet beat Russia's Elena Vesnina 6-3, 6-3 and Magdalena Rybarikova of Slovakia defeated Alexandra Dulgheru of Romania 6-4, 6-3.
Rising star Eugenie Bouchard of Montreal was scheduled to meet Alisa Kleybanova of Russia in an evening match on centre court.
American Serena Williams is the top seed at the US$2.369-million tournament.