Down 2-5 in the first set and facing set point, Keys rallied to turn the match around and win 7-6(2), 6-2 in an hour and thirty-six minutes.
Keys is one of several players on the Singapore bubble, wrestling for a spot in her first BNP Paribas WTA Finals Singapore presented by SC Global. She can even qualify this week as long as she reaches the final in Beijing; she took one step closer tonight against Kuznetsova.
"Some days I use it as my motivation to try harder, but sometimes it makes me more nervous and puts pressure on me," Keys told WTA Insider 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."
But Singapore looked a long way away when Kuznetsova broke Keys' serve to start out the match, keeping the American on the run and returning deep into the court to leave her opponent scrambling. Some loose forehands have Kuznetsova a second break for a 5-2 lead, and suddenly Kuznetsova was serving for the set.
The Russian held a set point and looked set to close it out, but a pair of double faults put Keys right back in it and the American ripped a backhand down the line to begin her comeback.
"I was 5-2 up and serving for the set two times, but then in a couple games Madison went for her shots and she made them," Kuznetsova said after the match. "There was a couple of netcords unlucky, too, and then the game was equal."
"She got her game on, and I lost mine, a little bit. That's basically what changed."
Keys broke back once more to level the match at 5-5 and the pair held firm to send the match into a tiebreak, where Keys allowed Kuznetsova just two points on her way to clinching the opening set.
"It just seemed like I was trying to figure out her serve and how she was playing, but I wasn't executing well," Keys explained to WTA Insider. "I was maybe just going for too much on my shots."
"I just - well, I just told myself a bad word and said, 'Get it together!' And after that I played a good game and got some confidence back."
The American broke Kuznetsova three more times in the second set to complete her comeback, taking the first spot in the quarterfinals.
Keys' road to the Beijing final won't get any easier, though; she will face Wuhan champion Petra Kvitova for a shot at the China Open semifinals after the Czech swept past defending champion Garbiñe Muguruza later in the day.