MELBOURNE, Australia - No.6 seed Elina Svitolina saved five break points in a crucial third game in the third set against rival Madison Keys to ultimately secure victory, 6-2, 1-6, 6-1, and reach a second straight Australian Open quarterfinal.

"I think I have been serving really good," she said after the match, assessing her fortnight thus far. "I have been returning solid. So, I always try to put pressure on the opponent. That's why I think I'm in quarterfinal. because I have been solid in all the matches. It worked really good."

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Svitolina had never beaten Keys in two previous meetings and avenged a heartbreaking 2017 US Open defeat to outlast the American after 96 minutes on Margaret Court Arena.

"I have been working on [my mindset] for past two years, trying different things, different techniques, and trying to find what works for me.

"At some stages of my career, some things worked; some didn't. I always try to find the motivation. My family helps me a lot to always pushes me to go for more.:

The Ukrainian led 4-2 in the final set of that Flushing Meadows encounter two years ago and was similarly imperious to open play on Monday, earning a double break lead and holding on to take the first set.

"Tennis is that kind of sport that you always get challenged almost every week, every tournament, every match. So you have to be ready to just give 100% each match. Of course if it's not your day today, you might lose, but in the end, you gave everything."

Though Keys has struggled with injury of late - opting to play her first event of 2019 in Melbourne rather than a pre-major warm-up event - she has been one to watch on the game's biggest stages, reaching the quarterfinals or better at three of last year's four Grand Slam tournaments.

Shaking off the disappointment of dropping her first set of the fortnight, she raced out to a 5-0 lead and eventually leveled the match with a chance to break early in the third.

Svitolina hit new heights at the end of last season by winning the BNP Paribas WTA Finals Singapore presented by SC Global, and was made to bring out that fighting spirit that helped her capture the biggest title of her young career, saving five break points in a game that lasted nearly 20 minutes and 11 deuces. 

"I knew that I had to be strong mentally and physically in that point, because the sun was very strong in that side, and I knew that I'm going to have a chance on the next game on her serve. So I think this was the key, just to be there 100%."

From there, the former World No.3 took control and didn't lose another game, booking her spot in the last eight, where she will play reigning US Open champion Naomi Osaka, who survived 2018 semifinalist Anastasija Sevastova in three sets.

"They have different game styles, so that's why let's wait who's gonna win," Svitolina said earlier in the day. "I've played against both of them, so we'll see how it goes.

"First I want to enjoy the day today. I did a great job today, so I don't really want to think about the next match now."

In all, she played pitch-perfect counterpunching to Keys' big swings, striking 22 winners to 16 unforced errors, and was clutch on her opportunities at net, approaching 19 times and winning 16 of those points.

As for Keys, she has plenty to be proud of with a positive winner-unforced error differential, striking 37 winners to 34 unforced errors, but will rue that pivotal game early in the final set after going two for two in her first two break point opportunities.