Li Na of China returns a shot to Dominika Cibulkova of Slovakia during their women's quarterfinals tennis match of the Rogers Cup tennis tournament in Toronto, Aug 9, 2013. [Photo/Agencies]

TORONTO - China's Li Na charged into Canada's Rogers Cup semis after a stellar performance Friday to knock out Slovakia's Dominika Cibulkova 7-6 (1), 6-2. [More about US Open hard court season]

Li defeated world's 20th-ranked Cibulkova with relative ease in their quarterfinals duel at the Rexall Center in Toronto, with China's only Grand Slam singles winner leading in all four of their head-to-head matches.

Cibulkova, who shocked tennis fans twice at the WTA Premier 5 event when she took out world No 9 Angelique Kerber in the first round, and No 10 seed Roberta Vinci in the third, was overpowered and outplayed by Li.

The Chinese player got an early lead on Cibulkova, but lost a bit of steam as she started struggling with her serves, losing points in five double faults, including two in one single game that led to her opponent breaking even at 4-4 in the set.

Despite these unforced errors, Li, runner-up of last year's Rogers Cup, played a strong and steady match against Cibulkova, who whipped the ball with brute force into Li's court the entire way. But the strong baseline player returned the balls with equal force, and eventually won the first set in a tie-break.

Dominika Cibulkova of Slovakia serves to Li Na of China during their women's quarterfinals tennis match of the Rogers Cup tennis tournament in Toronto, Aug 9, 2013. [Photo/Agencies]

"I was feeling a little bit different than yesterday because the opponent hit the ball different, but I was feeling today is even more tired than yesterday," said Li Na, who defeated Serbia's Ana Ivanovic in a close battle by 3-6, 6-1, 7-6 (5) in the third round. "I don't know, maybe I have a tough match (the) day before. "

"Today, I didn't have a lot of winners, but I was checking information and I still have 33," she added. "I thought I still can hit a lot of winners in (the) match."

Building on her momentum from the first set, Li took the second set and left the baseline once to show-off her sharp impressive net-rushing abilities when she ended a long exciting rally smashing a volley into her opponent's court, giving her a 4-1 lead.

"After (the) first (set) I was think about, okay, one set in the pocket, so feeling more confident," said Li. "So, yeah, second set just try to continue to hit the ball, because the first set was a little bit, I don't know, I tried to control a little bit so give her a lot of chance she can hit.  So I was running more first set."

Li will face Romania's Sorana Cirstea who beat 2011 Wimbledon champion Czech player Petra Kvitova 4-6, 7-5, 6-2.

Polish Agnieszka Radwanska, seeded third at the event, will also be heading into the semis after a tight match against Italy's Sara Errani after beating her 7-6 (1), 7-5 earlier in the day.

The two, who are meeting for the ninth time, squared off in a close first set, with Radwanska ramping up her game against her opponent in the tie-break. Changing up her tempo, Radwanska served up some strong volleys that gave her an early lead. From there on out, Radwanska broke out and won the tie-break 7-1 with ease.

Riding on her success from the first set, Radwanska took an early lead, but the steady and patient Errani, who scored a solid 7-5, 7-6 (3) win over France's Alize Cornet in the third round, caught up and broke back the set to 3-3.

Radwanska may have a tough road ahead, as she is set to face either world No 1 Serena Williams or Slovak player Magdalena Rybarikova in the semis.

Li Na's run-up to US Open:

Li Na battles her way into Rogers Cup quarters

Li Na dominates at Rogers Cup

Li Na's Wimbledon achievements:

Tough workout for Li Na in war of words

Li Na says she has achieved target

For the third time, Li Na reaches Wimbledon last eight

Li Na at 2013 Wimbledon