NEW YORK, NY, USA -- In a battle between Top 10 players, No.5 seed Elina Svitolina of Ukraine broke through to her first-ever US Open quarterfinal on Sunday night with a 7-5, 6-4 victory over No.10 seed and 2017 US Open runner-up Madison Keys of the United States.

"It was a really good performance from me," Svitolina stated, in her post-match presser. "Very solid, I would say, from the beginning until the end. I was feeling very good today physically, which helps my game, obviously. It's something that, yeah, very special for me to play in front of so many people. Night session in New York is always very special. To get a win is a special feeling."

Svitolina had made the fourth round of the US Open in the last two years -- losing to Keys in 2017 -- and finally went one step further with her 74-minute win over the American. Svitolina has now reached the quarterfinals or better at all four of the Grand Slam events, with her career-best major result being the Wimbledon semifinals earlier this summer.

"I was just trying to stay focused from the first point to the last point," Svitolina added. "Madison is a very powerful player, so you have to be at your best all the time and react very quickly. There was also lots of people, and the night sessions are very intense. So you have to bring your best game. It happened for me today, and I'm happy that it happened actually in the fourth round, and I'm finally in the quarterfinal here."

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Keys had defeated Svitolina in their first two meetings, but Svitolina notched her first win over the American in the fourth round of the Australian Open earlier this year, and has now leveled their head-to-head at 2-2.

"I had to take a look to analyze what I did wrong," Svitolina said, when reflecting on her 2017 US Open loss to Keys. "It was a very tough match that time. I was leading in the third set. It was a very, very painful loss for me, that one.

"I learned a lot, not only for this match but also for the future. With these kind of matches [where] you learn is a very painful experience, but I think in the end it helps you to improve your game and the way you have to handle the pressure points."

The Ukrainian won an astounding 92 percent of points on her first serve and never faced a break point in the encounter. She becomes the first US Open quarterfinalist representing Ukraine since Kateryna Bondarenko reached the last eight in New York City ten years ago.

"I think generally I was serving very good today," said Svitolina. "I was changing the pace, I was changing the placement very good. All the important points at the beginning gave me the confidence after to be more aggressive with my serve."

Keys, who reached the US Open final two years ago and the semifinals last year, was unable to make a dent on Svitolina's serve. Though the American had 32 winners to Svitolina's 10, Keys also had 39 unforced errors, well outpacing Svitolina's 13 miscues.

Through the first five games of the match, the players refused to give each other an inch, ceding no break points to their opponents. The power game of Keys pulled her through service games as expected, with five aces in the opener. However, Svitolina was up to the task on her delivery as well, dropping just four points on serve through 5-5.

It would be Svitolina who held the first big chance of the match, as a grouping of poorly-timed errors from Keys suddenly provided Svitolina with the first two break points of the evening. Keys served her way out of both, but a netted backhand by the American gave Svitolina a third chance. The third time was the charm for the Ukrainian, after Keys netted a forehand.

Svitolina had no trouble converting her first set point in the next game when Keys sent a backhand wide. The Ukrainian was superb on first serve in the set, getting 79 percent of those into play, and winning 21 of 23 points (91 percent) when she did so, never facing a break point.

At 1-1 in the second set, Keys fired a forehand winner to reach game point, but the American could not convert that opportunity. Svitolina clinched her second break point of that game with a backhand crosscourt winner, and grasped that chance to lead 2-1 after Keys blasted a backhand long.

Svitolina was just as impenetrable on first serve in the second frame as she had been in the first, and despite Keys wallopping some outstanding winners, the American was never able to recover from her deficit. Serving for the match at 5-4, Svitolina eased to triple match point, and the No.5 seed closed out the match following a third straight backhand miscue by Keys.

Next up for Svitolina will be another player in her very first US Open quarterfinal: Johanna Konta of Great Britain. No.16 seed Konta upset No.3 seed Karolina Pliskova of the Czech Republic earlier on Sunday to book a spot in the elite eight. Svitolina has beaten Konta all three times they have played at WTA-level.

"To be fair, they have all been very tough matches," Svitolina said about her rivalry with Konta. "She's a very tough opponent. She strikes the ball very good, and I have to react very quickly with my feet. Like today, I have to stay very solid from the baseline. I know a bit what to expect. I have been practicing a little bit with her. I have to step on court and be focused on my game. That's my goal for the next match."