Melbourne: A "shaking" Anett Kontaveit recovered from a set down to unseeded 18-year-old Iga Swiatek and fended off a late charge to fight her way into the Australian Open quarter-finals Monday.
The 28th seed is the first Estonian woman to reach the Melbourne last eight, where she faces a daunting task against fourth seed Simona Halep.
Poland's Swiatek, the youngest player left in the draw after Coco Gauff's exit, grabbed the first set on the tie break but Kontaveit finally prevailed 6-7 (4/7), 7-5, 7-5 in 2hrs 42 minutes.
"It was such a battle today so very happy I toughed it out, I'm shaking," said the 24-year-old Kontaveit, who is enjoying her best run in a Grand Slam and thrashed sixth seed Belinda Bencic 6-0, 6-1 in the previous round.
"I was just trying to stay as tough as I could and fight for every point."
Swiatek, ranked 56 and yet to win a WTA title, made a name for herself in only her second appearance at the Australian Open.
Swiatek, whose father was an Olympic rower, shocked Croat 19th seed Donna Vekic in the third round.
And she was on the way to another upset when she held her nerve in the tie break in Melbourne Arena to win the first set in 58 minutes when Kontaveit erred on a forehand.
Swiatek needed a medical timeout and heavy strapping to her left thigh before the start of the second set.
But it did not slow her, Swiatek breaking Kontaveit in the first game.
But neither player could consistently hold serve. They exchanged breaks throughout but the more experienced Kontaveit finally held in game 11 for a 6-5 lead, sealing the set when she broke Swiatek once more.
Kontaveit motored into a 5-1 lead in the deciding set and the match looked over.
But Swiatek threatened a late, remarkable comeback, winning four matches in a row for 5-5, before Kontaveit refound her composure to hold serve and then break the Pole for the match.
Two-time Grand Slam champion Halep will be the strong favourite in their last-eight encounter, but Kontaveit said: "Simona is so tough, but I have nothing to lose and will just go out there and enjoy the match."