San Francisco Frontiers - Rybakina crashes out of Madrid Open, Sabalenka reaches quarters

Earlier world number one Aryna Sabalenka overcame Naomi Osaka 6-7 (1/7), 6-3, 6-2 in a gripping battle to reach the quarter-finals.

Third seed Coco Gauff was eliminated in a three-set battle with Linda Noskova decided on a final set tie-break in an exciting fourth-round clash.

In the third round of the men's draw, second seed Alexander Zverev won in straight sets against Terence Atmane and Alexander Blockx earned a surprising win against world number five Felix Auger-Aliassime.

In the day's late match Kazakhstan's Rybakina, the world number two, was shocked by her 56th-ranked opponent.

Both players secured two breaks in the first set before Potapova edged Rybakina in the tie-break.

In the second set Rybakina captured her fifth break point of a long fifth game to nose ahead but lost the eighth and 10th games as Potapova triumphed.

"I'm speechless, I'm extremely happy, it was such a tough match and tough opponent," said Austria's Potapova.

"My team helped me today, they were there for me, big thanks (to them)."

Sabalenka, who has claimed titles at Miami, Indian Wells and Brisbane this year, was tested by her Japanese opponent but came back from a set and a break down to triumph.

"When (she) put me under pressure, I was able to pull out really incredible shots and incredible tennis. So I'm happy," said Sabalenka.

The first set between the two four-time Grand Slam winners was tight, with only one break point forced, by Sabalenka, which Osaka saved to hold for 2-1.

Osaka dominated in the tie-break, ripping into a 5-0 lead and then triumphing when Sabalenka lashed a return wide.

Reigning champion Sabalenka stepped up a gear in the second frame, although world number 15 Osaka dug deep to survive three break points and then managed to engineer a break for herself to take a 2-1 lead.

However, the Belarusian immediately broke to love and then again in the eighth game, serving out to take the second set.

Only Rybakina has beaten Sabalenka this year, in the Australian Open final, and the 27-year-old dominated in the third set, securing two breaks to triumph.

Sabalenka sealed her victory by serving to love with an ace to reach the last eight, where she will face American Hailey Baptiste, who beat Belinda Bencic in three sets, including losing a tie-break 16-14 in the second.

World number three Gauff, who had been dealing with a stomach bug this week, fell to a 6-4, 1-6, 7-6 (7/5) defeat by Noskova.

The Czech earned a decisive break in the fifth game of the first set, but American Gauff secured two of her own to claim the second.

Gauff moved two breaks up in the third but let the match slip away from her as Noskova pulled back to level 4-4.

The American led 3-0 in the tie-break before again she could not hold on.

- Zverev progresses -

Two-time former Madrid champion Zverev, ranked third in the world, showed his quality as he defeated Atmane 6-3, 7-6 (7/2) to reach the fourth round.

Serving well, Zverev kept the Frenchman at arm's length in the first set with two breaks.

The second was closer with Atmane battling well, and Zverev spurned two match points before triumphing in the tie-break.

Young Belgian Blockx, ranked 69th in the world, caused a shock with a 7-6 (7/3), 6-3 victory over Canadian Auger-Aliassime, his first win against a top-10 player.

"I had so much confidence," he explained.

"I didn't even think about panicking or losing my serve.

"I was playing well in the rallies, too, so I knew even if I missed a few serves, I could play the rallies."

Daniil Medvedev, who has reached the quarter-finals in each of the last two years despite not being a fan of clay, beat Nicolai Budkov Kjaer 6-3, 6-2.

Casper Ruud eased to a 6-3, 6-1 win over Alejandro Davidovich Fokina to reach the last 16, while Stefanos Tsitsipas, Francisco Cerundolo, Flavio Cobolli and Jakub Mensik also progressed.

R.Moore--SFF