In a battle between Americans, Lauren Davis notched the biggest upset of the Volvo Car Open thus far as she defeated No.2 seed Sofia Kenin, 4-6, 6-3, 6-4 to reach the round of 16.

Davis picked up her third career win over a Top 5 player with the grueling two-and-a-half-hour victory over World No.4 Kenin, as she improved to 2-1 on tour against the 2020 Australian Open champion and 2020 Roland Garros finalist.

"I’m super excited," Davis said, in her post-match press conference. "It was a really tough match, she obviously is an incredible player and one of the best competitors that I’ve seen. To have won this, in Charleston with these conditions, being so hot out, it’s really special for me."

79th-ranked Davis is now a win away from matching her career-best run in Charleston, when she reached the quarterfinals in 2015 before losing to eventual runner-up Madison Keys.

"I think this gives me some really good momentum," Davis said. "I always have that self-belief, but it’s just a matter of digging deep and applying that on the court. So the fact that I was able to do this today and show myself that I can beat a Grand Slam champion, it’s very cool, and I’m looking forward to the rest of the tournament."

2021 Charleston 500: Top points from Davis's upset of Kenin

2021 Charleston 500

Davis will now face another American, No.14 seed Coco Gauff, for a spot in the quarterfinals.

Gauff needed to survive a hard-fought tussle of her own as the 17-year-old overcame Liudmila Samsonova, 4-6, 6-1, 6-4 in exactly two hours of play.

This week's round-of-16 showing is the farthest Gauff has ever advanced in a WTA clay-court tournament. The 2018 Roland Garros junior singles champion fell in the second round in her two prior tour-level clay-court events, at Rome and Roland Garros last season.

The powerful Samsonova broke Gauff in the opening game of the match, and Gauff was never able to reclaim the break as the Russian methodically moved to the one-set lead. However, after dropping serve in the first game of the second set, Gauff charged into control, sweeping six games successively to level the match.

Samsonova rebounded with more aggressive hitting as she moved to a 3-1 lead in the decider, but Gauff won three games in a row to eke ahead 4-3 as she sought victory.

The American teenager dropped serve again, tying up the final set at 4-4, but dominated with return winners in the next game to break at love for a 5-4 lead and serve for the match. Gauff successfully powered her way to a hold and a spot in the round of 16 against Davis.

Two other teenagers were unable to win their second-round matches on Wednesday and join Gauff in the round of 16. First, 18-year-old Leylah Fernandez, a titlist in Monterrey last month, was defeated by Danka Kovinic, 6-4, 3-6, 6-3.

World No.91 Kovinic won back-to-back matches for the first time this season via her two-hour and 15-minute win over the Canadian teen. Kovinic will now take on No.3 seed Petra Kvitova in the round of 16.

And 19-year-old Emma Navarro saw her hometown run end at the hands of No.15 seed Veronika Kudermetova, as the Russian dispatched the Charleston resident, 6-4, 6-4, in an hour and a half.

Also, another upset occurred in the late afternoon on Althea Gibson Court, as Alizé Cornet ousted No.7 seed Elise Mertens, 7-5, 6-3.

Cornet saved two set points at 5-4 in the opening frame before storming back to win the final three games and taking the one-set lead after 75 minutes. The lengthy rallies continued in the second set until Cornet was able to grasp victory and move into the Charleston quarterfinals for the third time in her career.