DUBAI, UAE -- One of the most successful doubles teams of the past year was divided on opposite sides of the court in the second round of the Dubai Duty Free Tennis Championships on Wednesday, and it was No.7 seed Aryna Sabalenka of Belarus who defeated her regular partner Elise Mertens of Belgium, 6-4, 6-3, to make the quarterfinals.

"It was a tough match and [Mertens is] a great player," Sabalenka told the media after her win. "I knew it was going to be tough, and I was just trying to focus on each point and not think about anything else."

The pair of Top 25 players had split their four prior singles encounters, but it would be World No.13 Sabalenka who eked ahead in their head-to-head rivalry by 3-2 after her 90-minute victory over 22nd-ranked Mertens.

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Mertens and Sabalenka were a dominant doubles team on American hardcourts in 2019, winning the US Open, the Miami Open, and the BNP Paribas Open in Indian Wells last year.

Sabalenka, though, was the dominant player in their Dubai singles clash on the day, converting five of her nine break points, and winning nearly three-quarters of points off of her opponent's second serve.

"I think I’ve just a little bit cooled down on the court, and tried to think clear," said Sabalenka, when asked about her strong results since last year's US Open. "Just to focus on each point, and don’t try to overhit the ball, and look at the big picture."

In the quarterfinals, Sabalenka will have a test against No.1 seed Simona Halep of Romania, who squeaked past rising wildcard Ons Jabeur of Tunisia on Wednesday. Halep has won two of her three matches with Sabalenka, but Sabalenka won their last match, in Adelaide last month.

"Before I was trying to hit the ball as hard as I can!" Sabalenka laughed, when asked about her first two losses against Halep. "Every time I hit it, I’d think it’s not enough, because [Halep] hit it back.

"In the last match [when Sabalenka won], I wasn’t trying to do that, and like I said before, tried to be cool on the court. I just tried to push her, and don’t rush.

"Yes, she’ll give me a lot of balls back, and this is her game. She’s a really great player, and a big fighter. I will just try to play point by point, stay in the rally, and don’t be afraid of big points."

Mertens claimed the first break of the match after a tough tussle to lead 2-1, but the Belgian quickly let Sabalenka get back level in the next game, dropping serve at love with two double faults. Sabalenka began to power through her service games, easing to a 4-3 lead.

The players jostled back and forth in the following game on Mertens’s serve, as two game points for each combatant came and went. Another Mertens double fault gave Sabalenka a third break point, and on that occasion, the Belarusian came through, firing a forehand winner to grab a 5-3 lead.

Mertens still had some tricks up her sleeve, as she crunched a winning forehand of her own to close out the next game and pull back on serve at 5-4. However, Sabalenka continued to blast rockets during the Belgian’s service games, and the No.7 seed earned another break, and the set, with a hard-hitting rally that ended with a scorching forehand winner on the sideline.

Sabalenka pulled off a four-game winning streak to pull ahead 3-0 in the second set, but Mertens would not yield so easily, slamming a forehand passing winner down the line to earn break point at 3-1, then getting back on serve at 3-2 with another forehand winner.

However, the Belarusian struck right back, reclaiming her break lead after a double fault by Mertens on break point. Now up 4-2, the Sabalenka serve had clicked into place, and she hit two aces in the next game to reach 5-2 and put herself a game away from the quarterfinals.

Sabalenka would face one final test, when, serving for the match at 5-3, she faced two break points after a brilliant backhand winner by Mertens. However, Sabalenka found her aces when she needed them, blasting two in a row to get to deuce. The Belarusian moved through to the service hold from there, booking her spot in the quarterfinals.

Halep, Muguruza, Pliskova and other WTA Stars attend the 2020 Dubai Player Party