Former French Open winner Iga Świątek overcame some serious woes to outlast Kaia Kanepi in a 3-hour battle.
The 20-year-old bounced back from losing the first set to eventually triumph 4-6, 7-6 (7-2), 6-3.
This included the Pole serving 12 double faults.
She will have to improve dramatically in a short turn around of just 24 hours, as she faces the power play of Danielle Collins on Thursday.
The American will no doubt be the fresher of the two, winning in contrast, a comfortable straight sets.
Świątek and Kanepi both held their first three service games, before things began to get really interesting mid-way through the opening set.
A sloppy game from the Pole, including two double faults, gave the break on a plate to the Estonian.
At 36, Kanepi is one of the most experienced players on the WTA, and the seventh seed could ill afford to be handing out freebies.
The veteran made every use of the new balls, serving powerfully and tucking away a forehand smash to move 5-3 up.
Świątek then stumbled through her own marathon service game, that included a whopping nine deuces, and four break points/set points saved.
Kanepi’s service game was far from straight forward also, as she finally took the opening set after four deuces, and on her ninth set point, 6-4.
At the beginning of the second set, Świątek played another shaky service game to surrender the break to Kanepi.
A powerful cross-court backhand drive from the Estonian left her opponent on the floor, and it didn’t look like being the Pole’s day.
But Świątek dug in, and after four deuces on the Kanepi serve, she broke back.
At this point, the momentum suddenly shifted towards the Pole as she held serve before stealing the double break.
Świątek soon surged into a 4-1 lead, having won four games in a row, and looked to be cruising towards the second set.
But Kanepi held and broke back, before a comfortable hold saw her level at 4-4.
The second set trickled away on serve and a tie-break was needed to separate the pair.
But Świątek played the smarter tie-break, and four straight points saw her seal it 7-2, as Kanepi’s wayward backhand went long.
After a 69-minute second set, the youngster clenched her first, as Rod Laver Arena roared, with the match going to a decider.
All the energy was with Świątek, who broke at the beginning of the third, as she moved ahead 2-0, with Kanepi panting and struggling after over 2 hours in the Melbourne heat.
To her credit, she fought back, breaking the Warsaw native to level at 2-2.
But in a topsy turvy match, Swiatek broke and held to lead 4-2 and close in on a semi-final place.
The pole secured the double break but surrendered her own before finally prevailing in a marathon match point, to make the semi-finals for the first time in Australia.
After the match she had this to say: “I’m really glad that I still have my voice because I was shouting so loud.
“This match was crazy and without the energy of the stadium I think it would’ve been really hard to win it.”
