FORT WORTH, Texas -- Top seeds Barbora Krejcikova and Katerina Siniakova defeated No.6 seeds Xu Yifan and Yang Zhaoxuan 6-3, 6-3 to stay undefeated at the WTA Finals and secure their advancement out of the round-robin stage. The Czech duo improved to 2-0 in the Rosie Casals Group and have not lost a set. 

Krejcikova and Siniakova were confirmed as the winners of the Rosie Casals Group later in the evening after No.8 seeds Desirae Krawczyk and Demis Schuurs rallied to defeat No.3 seeds Coco Gauff and Jessica Pegula 3-6, 6-0, 10-5. Krawczyk and Schuurs improved to 1-1 in the group and eliminated Gauff and Pegula, who fell to 0-2, from contention. 

Krejcikova and Siniakova will face Gauff and Pegula to close out the group stage on Friday. Krawczyk and Schuurs will play Xu and Yang, with the winner joining the Czechs in the semifinals. 

Day 3 advancement scenarios

Champions at the WTA Finals last year, Krejcikova and Siniakova have not lost a match at the Grand Slams or WTA Finals this season, improving to 20-0 at the biggest events of the year. 

The Czech duo is bidding to become the seventh different team to defend a title at the WTA Finals, along with Martina Navratilova and Pam Shriver (1981-85, 1986-89), Gigi Fernandez and Natasha Zvereva (1993-94), Martina Hingis and Anna Kournikova (1999-00), Lisa Raymond and Samantha Stosur (2005-06), Cara Black and Liezel Huber (2007-08), and most recently Timea Babos and Kristina Mladenovic (2018-19).

Winning 91% of their first-serve points in the opening set, Krejcikova and Siniakova kept Xu and Yang at bay with a strong serving day. Using their all-court craft, the Czechs cruised through the first set, breaking serve twice and saving the lone break point they faced. 

Xu and Yang bounced back quickly, breaking serve to open the second set. But holding serve remained a challenge. They broke Krejcikova and Siniakova twice in the second set, but were broken three times, including in the penultimate game. The Chinese duo still had a chance to get back on serve in the final game, but a sublime forehand from Krejcikova wiped out break point and the Czechs converted match point to seal the win. 

The loss dropped Xu and Yang to 1-1 in the group, but the Chinese team remains in contention to qualify for the semifinals. Xu and Yang will face Krawczyk and Schuurs for the second qualifying spot out of the Rosie Casals Group on Friday.