MIAMI, FL, USA - No.9 seed Petra Kvitova found herself on the brink of defeat against American Sofia Kenin, but the two-time Wimbledon winner found a way to defeat the 19-year-old, 3-6, 6-2, 6-4, to reach the Round of 16 at the Miami Open for the first time since 2014.

"I have no idea how I won," Kvitova said during her on-court interview. "It was a really difficult match, mentally, for me to play a young player I didn't know. It's always a bit tough because those opponents play so well against me. I remember me when I was younger, how I played without fear and with nothing to lose. They play so aggressively, which she did today; she didn't really miss anything!

"I just tried to play more rallies and get into a rhythm."

Kenin made her major breakthrough last summer at the US Open - where she reached the third round as a wildcard - and appeared to use that experience of playing Maria Sharapova under the lights of Arthur Ashe Stadium at the start of her clash with Kvitova.

"She's a great mover. She can catch a lot of balls and put them back into the court. She serves well; she's not so tall, but she puts a good percentage of first serves in. I had to play a lot of rallies, and it was difficult to go to net because she reads the game so well."

After a slow start, Kvitova navigated through a tricky middle set that featured five consecutive service breaks, and rallied from 2-4 down in the decider to make it over the finish line after exactly two hours on Stadium Court.

She struck 35 winners to Kenin's 15, and converted eight of 14 break point opportunities while hitting a whopping 14 aces to eight double faults.

"In the second set, I tried to serve a bit better, have a better percentage of first serves, and try not to be so hectic and try to play into the court. That's not always easy for me, but that helped me today."

Up next for Kvitova is No.5 seed Jelena Ostapenko in what will be a rematch of their St. Petersburg Ladies Trophy quarterfinal, which Kvitova won in straight sets.

More to come...