The 14th seeded Kvitova, who is coming off a title at the Wuhan Open last week, dominated No. 2 seed Garbine Muguruza 6-1, 6-4 on Wednesday. Keys and Kvitova are among the players seeking a deep run in Beijing in hopes of moving into the top eight qualifying spots for the season-ending WTA Finals.
Keys fell behind 2-5 and faced a set point in the first set, before rallying for the victory. She likely needs to reach the finals this week to qualify for Singapore.
"Some days I use it as my motivation to try harder, but sometimes it makes me more nervous and puts pressure on me," Keys said of her potential to qualify for Singapore.
"I'm that close, I want to put myself in the best position possible and be able to walk away, whether I qualify or not, knowing that I did everything I could to get there."
Keys faces a difficult road in her effort to reach the finals, beginning with her quarterfinal match against the streaking Kvitova, who easily dispatched of the defending champion Muguruza in 72 minutes. Kvitova is on a seven-match winning streak and needs to win in Beijing to move into the top eight.
"I've played eight matches in 10 or 11 days, and I'm still going!" Kvitova told WTA Insider. "For sure, I'm feeling it; I do feel a few spots, but when I'm standing on the court, the adrenaline is there. I'm feeling very mentally tough right now, and that's my strength, for sure.
"I know my game is there, which helps a lot with confidence; I just have to hit it how I can, and that's most important."
In second-round action Wednesday, top seed Angelique Kerber, No. 11 Johanna Konta and No. 16 Elina Svitolina advanced in straight sets, while No. 5 seed Karolina Pliskova needed three sets to slip by Daria Kasatkina 3-6, 7-5, 7-6 (7) in a match that lasted just under two and a half hourse.
No. 12 seed Timea Bacsinszky was upset by Daria Gavrilova 4-6, 6-0, 6-4, while unseeded Carolina Garcia took out China qualifier Shuai Peng 6-3, 3-6, 7-4 (4). Peng upset No. 6 seed Venus Williams in the first round.
Konta, who is currently No. 14 in the rankings, also kept her hopes of qualifying for the WTA Finals in Singapore alive with her victory over Babos in a rain-delayed match.
"I think I'm most pleased with coming through a match like that. I think both of us were struggling to find our level out there," Konta said. "Definitely when there's been a rain delay and a day of play has been missed it does break up the rhythm a little bit.
"I think that showed in both our tennis out there. So it was just about who could compete a little bit better and I was fortunate I was able to find that little bit extra and come through that."
Konta will face U.S. Open finalist Karolina Pliskova in the third round.