After virtually gift-wrapping an unloseable first set, then suffering cramps with the finish line in sight, Kimberly Birrell somehow survived a three-hour marathon to outlast Romanian qualififer Jaqueline Cristian in a memorable quarterfinal on Day 4 of the Adelaide International.
No sooner had she thundered a backhand down the line to seal a 5-7 6-1 7-5 triumph - and a maiden WTA 500 semifinal - in 184 brutal minutes, Birrell sank to her knees on Centre Court at The Drive, elated and exhausted.
"Yeah, it's definitely up there, I would say," the popular Gold Coast wildcard said when asked where the victory ranks among her career achievements.
"I don't know what the right word is, but just the momentum shifts and how we both fought, I think we both completely emptied our tanks.
"Honestly, it's probably easier to say after winning, but it's one of the reasons I just love tennis so much because it tests you physically and mentally.
"I think it wasn't just about tennis out there today, it was about who could fight and who could keep believing in themselves.
"Really proud of myself that I just kept doing that until the last point."
Birrell needed to dig deep into that well of self belief on Thursday after surrendering the last five games of a taxing 78-minute first set, having led 5-2 and held five set points.
Birrell shrugged off that disappointment by sprinting through the second set, then narrowly coming out on top of Cristian – a typically physical claycourt specialist – in the third.
The Queenslander was assisted by the combination of a parochial home and a diet of salts and pickle juice once she felt her muscles start twitching.
Birrell admits had her backhand clincher skewed just wide and Cristian forced a tiebreak, it could have been a different story.
"I'm not sure what would have happened if I had to keep playing that last game," she said.
"I really needed that last point because I could really feel my right quad starting to cramp."
Birrell will face eighth seed Victoria Mboko, who knocked out reigning Adelaide and Australian Open champion Madison Keys 6-4 4-6 6-2.
The 19-year-old Canadian went up a break to start the second set via an insane passing shot before Keys worked her way back to square proceedings.
But the errors began mounting off the experienced No.2 seed's racquet in the third.
"It's not easy playing a top-10 player," Mboko said.
"Of course, going into the match I knew Madi was going to be very difficult to play, so I wanted to bring my A game.
"I just stayed really focused from the beginning."
Tommy Paul continues smooth progress
In the men's draw, second seed Tommy Paul took barely an hour to end giant-killing Aleksandar Vukic's run in clinical fashion, 6-3 6-2.
"I thought I executed the game plan really well," Paul said.
"I tried to stay unpredictable, tried to neutralise his serve and his forehand as much as I could, and not let him get too comfortable.
"I thought I did a pretty good job of that."
Paul will meet eighth-seeded Czech Tomas Machac, who has still yet to drop a set after ousting Spaniard Jaume Munar 6-4 6-4 on Showcourt 1.