MADRID, Spain - Top seed Naomi Osaka continued her impressive start to the clay court season by earning another milestone, ousting an in-form Aliaksandra Sasnovich, 6-2, 6-3 to reach the Mutua Madrid Open quarterfinals for the first time.

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"I think I played well today," she said in her post-match press conference. "But I knew that I had to because I've played her twice before already and it was on hardcourts and then I didn't know what to expect today so I tried to stay as focussed as I could."

Making just her second appearance in Madrid's main draw, the reigning US and Australian Open champion showed substantial improvements after a tough second round against Sara Sorribes Tormo, advancing after 83 minutes on Court Manolo Santana.

"I'm at a really good place right now, and I don't know, I feel like I'm having fun playing tennis again, which is always a good thing for me and I always play well if I have that mentality."

Osaka didn't lose a game when she played the Belarusian en route to her maiden major title in Flishing Meadows, though after having to withdraw from the Porsche Tennis Grand Prix in Stuttgart with an abdominal injury, she mused the switch from hardcourts to clay could make a difference in their rivalry.

"Hard is like my home," she said on Tuesday. "So, of course, I'll think about it but for me it's completely new."

Yet, the more things changed, the more they stayed the same for the Japanese youngster, who edged through the opening three games and saved two break points en route to a 5-2 lead, hitting 13 total winners in the first set to Sasnovich's 12.

"I don't necessarily see myself as a favorite, but I see myself as a seed, so I shouldn't necessarily be losing in the first round, and I have high goals for myself, but I have always been that type of person."

Where six of the first seven games went to deuce, Osaka was far more emphatic as the set came to a close, earning three set points at 0-40 and taking the second break off a Sasnovich double fault. 

She got off to a similar lead to start the second set, and though the unseeded Belarusian - who recently paired with new coach Vlado Platenik - was able break straight back, the World No.1 proved too strong, breaking once more and holding on to serve out the match in straight sets.

Looking to win one more match to hold off two-time Mutua Madrid Open champion for the top spot on the WTA rankings, Osaka next faces the winner of Dubai Duty Free Tennis Championships winner Belinda Bencic or surging qualifier Kateryna Kozlova, who stunned former World No.1 Karolina Pliskova in her last match.

"I think actually playing her on clay might be better for me because it's a slower surface and she hits really on the rise, so it might take away a little bit of her advantage," she said of Bencic, who won their most recent meeting at the BNP Paribas Open in March.

"I don't really know too much about Kozlova. I know that she's been playing really well recently, so that's something that I have to look out for."