MELBOURNE, Australia - No.28 seed Anett Kontaveit surged through a titanic three-set clash with Polish teenager Iga Swiatek, rallying from a set down and a late surge from her young opponent to become the first from Estonia to reach a first Grand Slam quarterfinal, 6-7(4), 7-5, 7-5 at the Australian Open.

Kontaveit looked to have things all wrapped up when she took a 5-1 lead in the final set, but Swiatek treated the Melbourne Arena crowd to a tense ending before the Estonian emerged victorious after two hours and 42 minutes on court. 

"I was just trying to keep going and fighting as much as I could," Kontaveit explained. "You know, there was a lot on the line, so I was just trying to do my best out there.

"It was a really, really tough match. Iga is a really good player. She was really tough and she was playing great tennis.

"I just had to stay tough. I mean, of course it wasn't easy. I feel like I could have done some things better, but I'm so proud of myself the way I was fighting through until the end.

"I think it definitely gives me a little bit of confidence getting through those close matches."

Swiatek made her first major breakthrough at Roland Garros last spring, where she upset Wang Qiang and 2016 Olympic Gold medalist Monica Puig en route to the fourth round. Playing another second week of a Grand Slam tournament, the 18-year-old cut a much more confident figure than the player who won just one game in this very round against former World No.1 Simona Halep in Paris, and broke serve to start the match.

Kontaveit was also looking for a first Grand Slam quarterfinal, having reached three other fourth rounds - two back-to-back in 2018 - and earned a career-high ranking of World No.14 shortly after reaching the Miami Open semifinals last April. The Estonian gamely broke back and twice led by a break in the opening set - serving for it at 6-5 - but Swiatek kept battling and forced a tie-break.

Tied at three points apiece after the Sudden Death's first change of ends, the Pole took control from there, winning four of the next five points to put herself one set from the final eight.

Though Swiatek took a medical timeout after the tie-break, the second set began in similar fashion to the first; Swiatek broke to open and Kontaveit quickly leveled, exchanging breaks once more as the No.28 seed moved within four points of a deciding set. Even as Swiatek thrilled the crowd with a casual tweener to tie up the set, Kontaveit kept pressing, leveling the match two games later with a backhand return winner.

Kontaveit carried that momentum into the third, rolling through the first three games and breaking Swiatek at love to move ahead 5-1. With the finish line in sight, Swiatek stepped in and capitalized on some tentative play from her higher-ranked opponent, smacking a backhand return winner of her own to break serve a second straight time, later levelling the match once more.

Somehow shaking off the disappointment, Kontaveit steadied to stop the run of games against her and earned her first match point when Swiatek pulled a forehand wide. It was all over one point later as the Estonian pushed her rival out wide and forced one last error to clinch the win.

In all, the Estonian struck 29 winners to 35 unforced errors, and while Swiatek finished the match with more winners, she also struck more errors (42 to 41) and converted 37% of her break point opportunities against Kontaveit's 64% (nine of 14).

Standing between Kontaveit and an Australian Open semifinal debut is former Halep, seeded No.4 this fortnight and into the quarterfinals after dispatching No.16 seed Elise Mertens in a rematch of their Qatar Total Open final from last February. Halep and Kontaveit played twice in 2017, with the Romanian winning both encounters in straight sets.

"I'm looking forward to playing against Simona," Kontaveit said. "She's a really great player, so I have got to play my best tennis.

"She's incredibly consistent. She's playing so well, moving so well, and I have definitely got to be consistent but try and play my game and be aggressive."

2020 Australian Open highlights: Kontaveit conquers Swiatek