NEW YORK, NY, USA - No.3 seed Karolina Pliskova kicked off her 2019 US Open with a tense, two-set win over compatriot and qualifier Tereza Martincova, 7-6(6), 7-6(3) to reach the second round.

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"Not perfect today, but I'm through so that's important," the often self-critical Pliskova assessed after the match. "Of course, the first rounds they are always a little bit nerve-wracking, I would say, for most of the players. It doesn't help that I played somebody from my country, because then it adds some extra nerves, which maybe they would not be there if she's from China or somewhere else!"

Pliskova beat both Williams sisters to reach her first major final in Flushing Meadows back in 2016, and displayed a similar level when it mattered most against her fellow Czech to win after one hour and 46 minutes on Louis Armstrong Stadium.

"In the end I had a lot of winners, when I saw the statistics. The serve was not great at all. So lost too many of my serves. I won two tie-breaks, so that's quite positive."

Still, the three-time WTA Ace Leader didn't have things all her own way, struggling on serve to start. Pliskova held serve just twice as Martincova came within two points of opening set in the tenth game. The former World No.1 duly broke back and forced a tie-break, securing the Sudden Death on her second opportunity.

"I think if I played like this a little bit earlier in the match, then the tie-breaks wouldn't have had to have happened," she mused, "So I'm impressed by this, but it's good that I played in the tie-break good."

Bouyed by the relief of being a set up, Pliskova, who reached back-to-back quarterfinals at this summer's Rogers Cup and Western & Southern Open, soon raced ahead by a 3-0, double break advantage. Martincova, who won three matches last week at the US Open's Qualifying Tournament just to make the main draw, was undaunted, soon leveling the set and twice getting within one game of a decider.

Pliskova stood her ground, forcing a second tie-break and ultimately emerging victorious on her first match point.

Despite a slow start, Pliskova ultimately ended the match with a positive winner to unforced error differential, hitting 35 of the former and 32 of the latter and improved her first serve percentage from under 60% in the first set to nearly 70% in the second.

"There's no plan B, no plan C for me. But anyway, I can still win matches without serve; I still have a lot of shots I can play. It's not like, if I don't have the first serve I cannot win because there is still second serve and then there is still the rallies.

"It's of course more difficult and maybe mentally a little bit more, because I'm used to getting free points from the serve. If it's not happening, then maybe I get more frustrated.

"I would love to have the serve that is working all the time. But even if the serve was not great today, I think in important moments I was able to just serve some good serve which is quite positive and hopefully it can just get better."

While Martincova managed to break Pliskova's serve an impressive six times, she couldn't consolidate and finished with 16 winners to 30 unforced errors.

"It wasn't really easy for me, because Karolina is a top player, who usually serves well," Martincova said after the match. "We had a problem on our serves from the start, and when I was up, I felt like I had to serve really well because usually on her serve, you don't have a chance. I think my mistake was that I was trying too much, more than normal.

"It was my first time on a huge court like this, and against this opponent, and so in the most important moments, I wanted to play better than normally."

Standing between the Czech powerhouse and a spot in the third round will Georgian qualifier Mariam Bolkvade, who won her first Grand Slam main draw match against American Bernarda Pera in three sets over on Court 9.