MONTREAL - Petra Kvitova overcame a mid-match slump to claim her first title of the season with a 7-5 2-6 6-3 victory over China's Li Na in the Montreal Cup on Monday.

In an entertaining but erratic encounter between two former major winners, the fifth seed's first tournament win since last October's WTA Championship will lift the Czech's confidence ahead of the US Open starting at the end of the month.

"It is great to have a good result in the Montreal Cup before the US Open. Finally I have played well," the world number six told reporters.

"It is a great preparation. I have played some good matches here and I hope that I can continue that."

Czech Republic's Petra Kvitova holds the championship trophy after her win over China's Li Na during the women's singles final match at the Rogers Cup tennis tournament in Montreal, Aug 13, 2012. [Photo/Agencies]

The 22-year-old's maiden victory on North American soil pocketed last year's Wimbledon champion $385,000 but it was not without drama.

The momentum shifted several times during the match but none more evidently than when Li won the first 16 points of the second set to race into a 4-0 lead after the 30-year-old 10th seed had dropped the opener.

"I knew that the second set she played very well," Kvitova added. "She was very aggressive and I didn't move very well. I knew I needed to calm down and keep patient."

Li, who remains without a title in 2012 after losing finals in Sydney, Rome and now Montreal, had started well before Kvitova eked out a 5-3 lead.

The 2011 French Open champion, who will return to the top 10 in the world rankings, fought back to level at 5-5 but was unable to covert a further four break points before suffering a bout of nerves on her next service game to drop the set.

China's Li Na hits a return during her women's singles finalmatch against Petra Kvitova of Czech Republic at the Rogers Cup tennis tournament in Montreal, Aug 13, 2012. [Photo/Agencies]

Li responded immediately, aided by some wayward play from her opponent, winning the first four games of the second set without dropping a point as Kvitova lost focus and struggled to land in the ball in the court.

That Kvitova made 16 unforced errors while hitting just one winner indicated just how off-target the Czech had become during the second set.

"I knew that she's a big fighter," Kvitova added. "I knew that it would be tough to win the third set."

The 22-year-old Czech regrouped at the start of the third and regained the advantage when Li overhit a forehand while trailing 2-3 to drop serve and Kvitova held her nerve to seal a much-needed victory.

"It's very tough against her because she plays the ball so deep," Li said. "Today I was feeling maybe like 70 percent (of the) time was like defence... to try to put ball back deep in the court."