It wasn't an upset based on the head-to-head - Cibulkova had won all three of the pair's previous meetings - but anytime the No.8 seed is taken out in their opening match by an unseeded player, it's a surprise. And the manner in which Cibulkova pulled it off was definitely surprising, fighting back from 4-1 down in the third set to put together a 67(0) 62 75 victory in all of two hours and 57 minutes.
"Angelique was putting everything back - her defensive game is really good, and I just had to be patient and aggressive at the same time today," Cibulkova said after the match. "You have to go for it. When you make some mistakes you get a little nervous - in a match it's a little bit different than in practice - but you just have to keep going for it, and in the end I made it today, so I was really happy."
Cibulkova's win over the World No.9 was her 19th Top 10 win. She has been as high as No.12 herself.
Ivanovic won her Rogers Cup in Montréal, but still loves coming to the Toronto edition of the event.
"I actually love coming here," she said. "I haven't had a chance to go anywhere this year yet, but hopefully later in the week. I've been to Niagara Falls and that was a really nice experience. Also, I have a childhood friend who lives here now, so that's another nice thing to do and catch up."
No.13 seed Kirsten Flipkens also advanced, albeit in somewhat bizarre fashion - taking on Venus Williams, Flipkens dropped the first set at love and faced double break point serving at 4-4, 15-40 in the second set, but some inspired play and an increasingly erratic Williams helped turned the match around, with Flipkens eventually outdoing the former No.1 in a see-saw three-setter, 06 64 62.
"I wasn't expecting to play that well in the first set, so in the second set I just didn't handle it well - I was pretty close to closing that match out there," Williams said. "Then I got down in the third. I think I just sprayed a few balls and got a little tentative. I definitely didn't make the best choices out there, but in general it was really fun to be back out there again, and I'm getting ready for Cincinnati next week."
The always-gracious seven-time Grand Slam champion had very kind words for Flipkens, though.
"My opponent has been playing awesome this year, and she definitely showed a lot of resilience by fighting back today," Williams said of Flipkens. "It's never easy to lose a 6-0 set and come back."
No.11 seed Maria Kirilenko and No.15 seed Jelena Jankovic were among the winners on the outside courts, as were Carla Suárez Navarro, Ekaterina Makarova, Alizé Cornet, Magdalena Rybarikova, Francesca Schiavone, American qualifier Lauren Davis and Canadian wildcard Sharon Fichman.