Ekaterina Alexandrova and Veronika Kudermetova will have a Libéma Open rematch in the quarterfinals of the bett1open after they upset No.5 seed Coco Gauff and No.1 seed Aryna Sabalenka, respectively, in 

Alexandrova extended her winning streak to seven matches with a 75-minute, 6-4, 6-0 upset of Gauff to start the day's play, before Kudermetova followed with a 6-2, 7-6(2) win over Sabalenka.

Alexandrova, who successfully defended her 's-Hertogenbosch title last week in a dramatic three-set triumph over Kudermetova, notched her second Top 10 win of the year following her defeat of Belinda Bencic in Miami, and the 11th of her career overall.

Kudermetova, meanwhile, beat Sabalenka in the second round in Berlin for the second consecutive year. Twelve months ago, she won 2-6, 7-5, 6-4. 

The 28-year-old Alexandrova had lost to Gauff from two match points up in their only previous meeting, 7-6(3), 2-6, 7-6(8) in the first round of Dubai 2021. However, after falling behind 3-1 in the first set, she won 11 of the last 12 games to reach the Berlin quarterfinals for the second time in her career.

"Honestly, I don't know," said Alexandrova afterwards when asked about her strong grass-court form. "Grass is not my favorite surface, but somehow I'm managing to play so well on it. And maybe the score looks easy, but it's never like that because she played amazing. I needed to stay focused during every single point to keep it that way. I'm just hoping I can keep this form as long as I can."

Key games: A bright start for Gauff, in which she showed off her court coverage and net skills en route to breaking Alexandrova for 3-1, proved to be a false dawn.

Alexandrova immediately broke back and thereafter won all three of the contest's multi-deuce tussles to run away with the scoreboard.

The first was at 4-4 in the first set. Gauff saved four break points in this game alone with service winners, but a stellar volley from Alexandrova converted her fifth. She duly served out the opener with little fuss.

The second set opened with two tight games. In the first, Gauff found superb winners to fend off the first three break points, but was unable to reach game point herself -- and conceded the break with a netted forehand on the fourth break point. She had two opportunities to break Alexandrova back immediately, but was stymied by solid serving from her opponent.

Gauff had her share of crowd-pleasing winners in the second set, notably two reflexed counterpunching reactions. However, she was undone by a slew of cheap mistakes, including 27 unforced errors on the forehand side alone. By contrast, Alexandrova was rock-solid in executing her first-strike tennis.

Kudermetova scores third career Top 3 victory

Kudermetova now boasts a Top 3 win on all three surfaces in her career, having beaten Jessica Pegula at the Mutua Madrid Open this spring, and Karolina Pliskova at the Western & Southern Open in 2020. 

She broke Sabalenka three times in 1 hour and 39 minutes, including twice in the first four games of the match to sprint out to a 4-0 lead. Trailing 6-2, 4-2, Sabalenka won three straight games, and later at 6-5, was two points away from pushing the match the distance at deuce on Kudermetova's serve. 

In the end, a commanding 6-1 start for Kudermetova in the tiebreak helped push her over the line.