(Photo credit: Andy Abeyta/The Desert Sun / USA TODAY NETWORK via Imagn Images)

Unseeded Austrian Anastasia Potapova surprised No. 2 seed Elena Rybakina of Kazakhstan and won a 7-6 (8), 6-4 battle in the Round of 16 at the Madrid Open on Monday.

Two of the top three seeds were shown the exit door, as Czech 13th seed Linda Noskova defeated No. 3 seed Coco Gauff 6-4, 1-6, 7-6 (5). Top-seeded Aryna Sabalenka of Belarus survived a tough test from No. 14 Naomi Osaka of Japan but advanced in three sets.

Potapova's victory took one hour and 53 minutes and finished just after midnight local time. In the field as a lucky loser, she is now set to play a WTA 1000 quarterfinal match for just the fourth time.

Rybakina turned a 2-0 deficit into a 5-3 lead in the first set, but Potapova rallied to tie it at 5-5 and 6-6. The pair traded one-point leads in a tightly contested tiebreaker before Potapova won it on her third set point.

Potapova then trailed Rybakina 4-2 in the second set before she ripped off the final four games in a row. She ended the match having saved 7 of 10 break points and having won 75.5% of her first-service points (37 of 49).

Gauff, meanwhile, squandered a 4-1 lead in the third set and let Noskova move in front 6-5 before forcing a tiebreaker. There, Gauff led a 4-2 lead slip away.

Noskova hit eight aces with seven double faults, while Gauff fired 13 aces and committed six double faults. Gauff also saved 7 of 10 break points, but it was not to be.

'I know the match is not over until it's over,' Noskova told reporters. 'I was kind of saying to myself that I'm still close ... even though it's 1-4. I just wanted to find my rhythm and my game all over again.'

Sabalenka found herself a set and a break down when Osaka broke her serve in the third game of the second. Osaka won a marathon sixth game to tie it 3-3, but from there Sabalenka took nine of the last 11 games of the match, prevailing 6-7 (1), 6-3, 6-2.

'Oh my God, that was incredible level,' Sabalenka said after improving to 2-1 all-time against Osaka, the four-time major champ. 'She played incredible tennis. I feel like I just got lucky in a couple shots in the third set, that's why it went that fast.'

Sabalenka became the sixth woman to reach 150 match wins at WTA 1000 tournaments.

Her next opponent is 30th seed Hailey Baptiste, who reached her second WTA 1000 quarterfinal by enduring a second-set marathon to beat No. 11 Belinda Bencic of Switzerland 6-1, 6-7 (14), 6-3. Baptiste double-faulted three times during the second-set tiebreaker, and Bencic was credited with six match points saved in all.

In other matches, No. 9 seed Mirra Andreeva of Russia needed two hours and 53 minutes to get past Hungary's Anna Bondar 6-7 (5), 6-3, 7-6 (5); Canadian 24th seed Leylah Fernandez beat 31st seed Ann Li 6-3, 6-2; No. 26 Marta Kostyuk of Ukraine eliminated Caty McNally 6-2, 6-3; and Karolina Pliskova of the Czech Republic advanced past Solana Sierra of Argentina 6-4, 6-3.

--Field Level Media