Sabalenka, who has claimed titles at Miami, Indian Wells and Brisbane this year, was tested by her Japanese opponent in the fourth-round clash but came back from a set and a break down to triumph.
“I was just trying to take one ball at a time and my team was there for me, they really (pushed) me to keep fighting, and I’m really happy that I didn’t give up and I was pushing until the very last point,” said Sabalenka on court.
She later told reporters: “When (she) put me under pressure, I was able to pull out really incredible shots and incredible tennis. So I’m happy.”
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.
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 Elena Rybakina has beaten Sabalenka this year, in the Australian Open final, and the 27-year-old dominated in the third set, securing breaks in the fifth and seventh games while Osaka could not put pressure on her opponent’s serve.
Sabalenka sealed her victory 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.
“She’s an incredible player, we had a really tight match in Miami, and especially here in Madrid, I think this surface suits her game,” added Sabalenka.
Osaka said she was happy with pushing Sabalenka to the wire after going down in straight sets when they met at Indian Wells.
“I feel like every game was super close. I think… I could potentially match her in power,” said Osaka.
“I feel like in Indian Wells I was a little overwhelmed. Here I did a little bit better.
“Obviously, she’s the number one player in the world, so it was a really cool match for me to know that I’m kind of there.”
World’s No. 2 Rybakina eliminated
Australian Open champion Rybakina fell to a shock 7-6 (10/8), 6-4 defeat by Anastasia Potapova on Monday in the Madrid Open fourth round.
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).”
Gauff dumped
Third seed Coco Gauff was eliminated in a three-set battle with Linda Noskova, which was decided on a final-set tie-break.
World number three Gauff, who had been dealing with a stomach bug this week, fell to a 6-4, 1-6, 7-6(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 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 defeated Daniel Merida 6-4, 6-2.
