Just one day after seizing the WTA top ranking position, Caroline Wozniacki of Denmark survived injury scare to beat Ana Ivanovic 7-6(1), 6-4 in a quarterfinal clash at China Open on Friday.

After beating Petra Kvitova of the Czech Republic 6-3, 6-2 in the third round on Thursday, the 20-year-old Dane overtake the former world No. 1 Serena Williams to top the WTA world rankings.

But in the match against Ana Ivanovic, a former world 1st-ranked Serb, the blonde Wozniacki could not take an early lead. After the two players each broke once, the first set saw the two sides tying at 6-6. The 22-year-old Ivanovic seemed to be lost in the tiebreaker, lagging behind 6-0 before surrendering the tiebreaker 7-1.

Wozniacki continued her sound form in the second set, until the 20-year-old suffered an surprising injury as she was 3-1 leading. The Dane wrenched her left knee when hitting back a baseline ball and could not stand up right away. The match was intermitted as Wozniacki received medical treatment.

As suspicions rose that the top seed might retire due to injuries, Wozniacki walked back on the court with bandages wrapping over her left knee. Although suffering minor injuries, the first seed did not lose control of the set. After another exchange of breaks, Wozniacki secured the one hour, 53 minutes win.

It was the first time for Wozniacki to defeat Ivanovic in her professional career. Back in 2008, the Dane suffered two straight losses against Ivanovic, who ended the season on top of the WTA rankings. However, the currently 36th ranked Serb has turned out to be the first opponent that Wozniacki beat as a world No. 1.