LINZ, Austria - Top seeds and longtime doubles partners Aryna Sabalenka and Elise Mertens kept hopes of an Upper Austria Ladies Linz finals clash alive with a pair of singles victories on Thursday.

“I think this is the first time that this has happened, and it’s really cool," Sabalenka said of sharing the Top 2 seeds. "I would like to play her in the finals, and that would be something really special.”

The 2019 US Open champions went back-to-back on Centre Court, first with Sabalenka easing past Swiss qualifier Stefanie Voegele, 6-0, 6-3 in 67 minutes. Mertens then rallied from a second set hiccup to survive former World No.2 Vera Zvonareva, 6-4, 5-7, 6-2, after two hours and 32 minutes.

Sabalenka won a sixth straight match, having captured the J&T Banka Ostrava Open - along with the doubles title with Mertens' help - and enjoyed a 26-minute opening set before Voegele forced a tense finish in the second set.

“I think I started really well, going for my shots and not missing at all. She started playing more aggressively and using more power in the second set. I wasn’t as ready for that, but I adjusted quickly and that helped me win the match.”

After playing several titanic matches in Ostrava - including one in which she trailed 6-0, 4-0 against Sara Sorribes Tormo - Sabalenka has been much crisper on key points, saving all nine break points faced against Voegele.

Linz 2020 highlights: Sabalenka bests Voegele

“I’m working on my focus on the court. I’ve had a lot of matches where I was out of in the first set, and then by the time I was able to come back, we’d be in a third set, and those can be 50/50. So, I’m trying to put pressure on my opponents from the beginning of every match. I’ve also been working on the variation of my shots, so I’m not just one kind of player and can use every shot I have in my pocket.”

Sabalenka, who next plays French qualifier Oceane Dodin for a spot in the semifinals, could not only secure a Top 10 finish by reaching the final, but a victory in Linz could also tie her with Simona Halep for most titles won in 2020; the Qatar Total Open champion currently trails the former World No.1 3-2.

“I feel like when I’m overthinking about where I’m trying to put this ball in a certain place, I’m missing. When I’m freer on court, I don’t feel the same pressure; I know where the ball should go, and I hit it without applying too much power. My preparation and swing is at 100% when I feel free, and that helps me fly on the court and do all I can.”

Later on, Mertens took the court for an intriguing encounter with Zvonareva, a two-time Grand Slam runner-up and 2008 Olympic bronze medalist.

After injuries sidelined her for much of last year, the Russian won a fifth major doubles title - second in women's doubles - at the US Open alongside Laura Siegemund. Earning a wildcard in Linz, she overcame a generational battle with Ukrainian teen Marta Kostyuk to play Mertens, who herself has enjoyed solid results post-lockdown.

Breaking to open the match, Mertens staved off a late surge from the veteran to capture the opening set. Undaunted, Zvonareva rebounded in some style by winning the first four games of the second set before taking a 5-2 lead.

Momentum shifted once more as the Belgian leveled the set, only for Zvonareva to sweep the final two games and force a decider.

Mertens mirrored her experienced opposition in the final set, taking a 4-0 lead of her own before ultimately breaking for victory with a letcord winner.

Up next for the two-time US Open quarterfinalist is No.5 seed Veronika Kudermetova, who advanced after three sets with Arantxa Rus earlier in the afternoon.