LINZ, Austria - Former World No.2 Vera Zvonareva held off a tough test from recent Top 100 debutante Marta Kostyuk, easing past the Ukrainian teen, 6-4, 6-2 to reach the second round at the Upper Austria Ladies Linz.

Zvonareva, who turned pro two years before Kostyuk was born, navigated a tricky opening set to ultimately dispatch the youngster after 89 minutes on Centre Court.

"I knew she's a great, up and coming player, and a fighter on the court," she explained after the match. "I was an up and coming player like, twenty years ago! I've seen her play a couple of times, but have never practiced or played in the past. I knew it was going to be a tough match, and that I'd need to play my best to beat her."

A former Australian Open junior champion, the 18-year-old Kostyuk has enjoyed impressive results since her initial WTA breakthrough back in 2018, pushing eventual US Open champion Naomi Osaka to three sets in the third round, qualifying for a Roland Garros main draw debut and reaching a pair of ITF Pro Circuit finals that pushed her to a career-high ranking of World No.97.

"When I was her age, it was different. I had no idea what it was like to be on tour and I had no experience. Things seemed easy at first, transitioning from juniors. I never had to play a lot of ITF tournaments because my transition was so fast. I came up the rankings very fast, and you start taking things for granted. It's sad to lose matches, but you don't think as much about injuries or how anything can happen to stop this rise. Sometimes you get frustrated for no reason. I'm much calmer now, more aware of the ups and downs, because everyone has them, and you have to be able to manage them."

A wildcard in Linz, Zvonareva is making up for ground lost after an injury-addled 2019, one that had started with a return to the Top 100 after giving birth to daughter Evelyn three years prior. Reaching the Round of 16 at the Western & Southern Open as a qualifier, her most memorable result since tour action resumed was in doubles, where she won the US Open with Laura Siegemund - her first major title since 2012.

"I think singles and doubles are different games. It was great to be at the US Open and to have that trophy. I've had some great success in doubles before, but just playing a lot of matches, being out there against great players. Even if it's doubles, it still helps, especially after the long break I had in 2019. I'd only just started competing before the tour was suspended. Overall, it was a year and a half break, so it was important to be back on big courts against top players."

In an intriguing generational battle, Zvonareva thrice led by a break in the opening set; while Kostyuk twice clawed back, Zvonareva turned the tables on the teen in the ninth game, breaking on her second opportunity and serving out the set at love.

"It's always difficult to play a first match at a tournament. In the beginning, I couldn't find my rhythm, with a few mistakes, but I felt I got better and better in the match."

Frustration began to build for Kostyuk as she fought to remain in contention in the second set, saving two break points Zvonareva threatened to take a double break lead. Nearly leveling proceedings in the sixth game, the Ukrainian fell behind once more on serve as Zvonareva found herself serving for the match.

Engineering two match points, Zvonareva pulled off one last service winner to edge of the finish line, where either No.2 seed Elise Mertens or qualifier Anhelina Kalinina await.

"I'm just enjoying my time on the court, and I want to play as many matches as I can to prolong my career. Maybe I have a few more months, maybe a few more years. I'm not setting any limits for myself. I was up against a young, up and coming player today, and we were able to fight on court and play a good match. After so many years, my fitness and mentality are still there, and I still have the desire to compete. If my mindset is like that, the age doesn't matter to me, and it's just about two players competing on the court."

Earlier in the day, 2018 champion Camila Giorgi survived a second set hiccup to defeat Sara Sorribes Tormo, 6-3, 5-7, 6-4, and will next play either French Open semifinalist Nadia Podoroska or Irina-Camelia Begu, who face off on Wednesday.

2019 St. Petersburg highlights: Zvonareva stuns Goerges to reach quarterfinals