Madison Keys of US competes during the WTA Finals round robin match against Dominika Cibulkova of Slovakia at Singapore Indoor Stadium, Oct 25, 2016. Madison Keys won 2-0. [Photo/Xinhua]

In the second Red Group encounter, Keys defeated No.7 seed Cibulkova 6-1, 6-4 for a 1-1 sheet, as the victory marked the first win for Keys, who made her debut in WTA Finals here in Singapore.

"That was a little bit better than the first round. Definitely really happy with how I kind of turned things around. You know, just went out and played my game. I think I did a lot of things a lot better," Keys told the press.

Cibulkova for her part said she was frustrated with her performance. "Today (I) was a little bit frustrat(ed) on the court because I was feeling good after the match against Kerber. Today I just couldn't play my tennis. Couldn't get in the rhythm," the Slovakian said.

Asked how she feels at the WTA Finals, also her first appearance, Cibulkova said that the feeling is hard to describe and "really different."

She stressed it's very new experience for her. "I'm happy to be here and to see and to live it, but I'm hoping to win a match. I will do everything to win a match this year," said Cibulkova.

As for qualification scenarios in the Red Group, Kerber is the only one in full control of her fate on Thursday. If she beats Keys, she'll qualify for the semifinals. On the same day, Halep will face Cibulkova.