Holder Wozniacki, Kvitova book WTA Finals berths

WTA Finals holder Caroline Wozniacki and former champion Petra Kvitova have clinched places in this month's season-ending tournament in Singapore, the WTA announced on Thursday.

The pair join world number one Simona Halep, Angelique Kerber and Naomi Osaka who have already qualified for the Oct. 21-28 tournament at the Singapore Sports Hub.

"Winning the WTA Finals last year was a huge accomplishment for me and helped my confidence leading into this season," Wozniacki, who won the Australian Open in January, said.

"I look forward to coming back to Singapore to try and defend my title," the 28-year-old Dane added.

Wozniacki secured her the spot after a routine 7-5 6-4 win against Estonia's Anett Kontaveit at the China Open in Beijing on Thursday.

Exciting day today!! Officially qualified for the Year End Championships in Singapore! Can’t wait to be back and compete with the best players in the world and try to defend my title 💪🏻😊 pic.twitter.com/k0XIX1Vrp9

— Caroline Wozniacki (@CaroWozniacki) October 4, 2018

Czech Kvitova, who won the WTA Finals title in 2011, has qualified for the first time since suffering career-threatening injuries to her left playing hand after a 2016 stabbing that kept her out for six months.

Kvitova, who lifted the Wimbledon trophy in 2011 and 2014, required surgery after trying to protect herself from a man wielding a knife who gained access to her apartment.

"It will be my first time back there (the WTA Finals) since I came back to tennis so it means a lot to me and has always been one of my big goals for the season," Kvitova, who has won five titles this season, said.

Juchuuuu so happy to be heading back to Singapore. This means more to me than you know. Thanks for your support this year and I can't wait to compete at the @WTAFinalsSG 💪 https://t.co/i7ZAMbQ1oj

— Petra Kvitova (@Petra_Kvitova) October 4, 2018

The top eight singles players at the $7 million prize money event will compete in a round-robin format with the winner taking home the Billie Jean King Trophy.

The top eight doubles teams will compete for the Martina Navratilova Trophy.