In a see-saw encounter, that kept the crowd on Philippe Chatrier guessing as to the outcome until the very end, it was Kuznetsova who produced the final flourish to take her over the line, 64 46 63.
A combination of injuries and loss of form over the last few years have seen Kuznetsova, once a fixture in the Top 10, slowly slip down the rankings. But against Kerber, she looked anything but a spent force, moving as swiftly and striking the ball as crisply, particularly on the forehand, as she has since lifting the title here four years ago.
"I've had some tough times, where I was not kind of playing 'my' game," Kuznetsova said in her post-match press conference. "But Grand Slams always bring the best out of me.
"It just comes naturally and I don't have to push myself to find that extra level here because it's the French Open. I kind of get into the zone automatically."
The Russian's aggressive approach forced the World No.8 into the role of counterpuncher. But despite spending most of the opening exchanges on the back foot, it was Kerber that struck first, breaking for a 4-3 lead in the opener.
Yet this setback only succeeded in strengthening her opponent's resolve; Kuznetsova broke back immediately before reeling off the final two games of the set amidst a flurry of eye-catching winners.
This pattern continued into the second set, but just as the match appeared to be drifting away from her, Kerber upped the ante to break twice in quick succession, the second with a trademark down-the-line forehand winner. The set soon followed and when she broke once more at the start of the decider, a place in the last eight beckoned.
Kuznetsova had other ideas, however, regrouping to reel off the next four games and take a stranglehold of the match. It was a grip that would not loosen, closing the match out at the first time of asking with an umpteenth forehand winner.
"I think I should have played better in the second set, but when I was in front I couldn't push on," Kuznetsova said. "I knew it was very important not to make the same mistake in the last set.
"I thought I'd try to play longer rallies, and then go for my shots when I had a good opportunity."
Standing between her and a place in the semifinals is Serena Williams, after she saw off Roberta Vinci, 61 63, to stretch her current win streak to 28. Williams has won six of their eight meetings, although the only encounter at Roland Garros went the way of Kuznetsova, who triumphed in three sets on her way to the title in 2009.
World No.39 Kuznetsova will go into the match as a heavy underdog, and it is a role she is only too happy to embrace. "She's the best in the world at the moment and has been playing unbelievable tennis. I'll just go out there and play my game. Sometimes I can be very good. Sometimes not so good. Let's cross our fingers that I will have a good day against her!
"I don't care if I'm an underdog or not. I'll just go out there and try to do my best."