MONTREAL (AP) -- Top-seeded Jelena Jankovic of Serbia lost her second-round matchup with qualifier Iveta Benesova of the Czech Republic 7-6 (3), 6-3 on Tuesday night.
Jankovic has played only four matches in three tournaments this month after missing two weeks with an ankle injury she says is completely recovered.
"I didn't really feel like a top-five player out there,'' said Jankovic, who has never won the Rogers Cup. "My game hasn't been at the top level for the last couple of tournaments.''
The US Open is the only Grand Slam where Jankovic has reached the final, losing to Serena Williams in 2008.
Jankovic is hoping she can find her game in the short time that remains before the start of the final Grand Slam of the year on Aug. 30.
"I really wanted to play matches here, and at the last tournament, but I didn't do that and now I haven't played many matches before the US Open,'' Jankovic said. "So I'll just try my best over there, and hopefully I'll be better.''
Benesova, ranked No. 75 in the world, won her sixth match in the past five days, winning three on the weekend in qualifying plus her first-round singles and doubles matches on Monday.
"I think it was good for me because I haven't had a very good season this year,'' said Benesova, who improved her 2010 singles record to 17-18. "It was good for my confidence.''
It was the biggest win of Benesova's 12-year pro career, her previous best being a victory over then-No. 5 Mary Pierce in the second round of the 2006 Australian Open.
"This is definitely the biggest victory of my career, I'm just very excited,'' Benesova said. "It was a great match for me.''
Benesova will face the winner of the second-round match between France's Marion Bartoli and Japan's Kimiko Date-Krumm.
Jankovic got off to a strong start, winning her first two service games at love and breaking Benesova to go up 5-3 in the first with a chance to serve out the set. But Benesova broke right back and forced a tiebreaker, winning the final three points to take it 7-3.
The players exchanged breaks in the second set until Benesova broke Jankovic again to go ahead 5-3 and served out the match, standing on the baseline with both hands on her head as the crowd roared approval.
No. 17 seed Marion Bartoli earned an easy 6-1, 6-0 win in 69 minutes.
The eighth-seeded Vera Zvonareva made quick work of Kazakhstan's Yaroslava Shvedova, winning their second-round match 6-2, 6-1 in 67 minutes.
No. 11 seed Svetlana Kuznetsova needed three sets to defeat fellow Russian Anastasia Pavlyuchenkova 7-5, 4-6, 6-1.
From 2006 to 2009 Kuznetsova was a perennial top-five player, reaching a career-high No. 2 in 2007, but she arrived in Montreal ranked 16th in the world.
Kuznetsova said she feels she is slowly getting back to that top-five form.
"Before, I was more aggressive, I was going for the balls, and I think I have that back,'' Kuznetsova said. "I think my game is better. I feel like I'm back, I'm back in my game and it all depends on me.''
No. 10 seed Victoria Azarenka of Belarus beat Kateryna Bondarenko of Ukraine 6-1, 6-1, 15th seed Flavia Pennetta of Italy ousted Slovakian Daniela Hantuchova 6-0, 7-5, and 18th seed Nadia Petrova of Russia was stretched to the limit 7-5, 4-6, 6-3 by Lucie Safarova of the Czech Republic.
Date-Krumm, the 39-year-old who received entry into the main draw only after Maria Sharapova pulled out Sunday night with a heel injury, won her first-round match 7-6 (4), 4-6, 6-2 over Romanian qualifier Monica Niculescu.
After three qualifiers advanced to the second round on Monday, two more advanced Tuesday with victories by Ekaterina Makarova of Russia and American Bethanie Mattek-Sands.
Russia's Maria Kirilenko had a 6-0, 6-3 victory over Slovakia's Dominika Cibulkova, who made the final here in 2008.