The imported Aussie 'Dasha' continued her welcome revival but had to really sweat it out on another scorching day at Roland Garros before subduing her most dogged of opponents, Swiss qualifier Susan Bandecchi, 7-5 7-6 (13-11) on Thursday.
That hard-fought win in the 32C afternoon heat was a welcome tonic for the Australian challenge after Queensland giant-killers Kimberly Birrell and Adam Walton both crashed back down to earth with deflating losses.
In an epic second-set tiebreak lasting 17 minutes, Kasatkina eked out seven match points before finally killing off the stubborn challenge of clean-hitting world No.215 Bandecchi and will now vie with Alex de Minaur, who'll face Jakub Mensik on Friday, to again be 'last Aussie standing' at RG, just as she was last year.
Overcoming "brutal" conditions, she'll now face Sabalenka, 7-5 6-2 victor over Frenchwoman Elsa Jacquemot, for a 10th time. The Belarusian leads 7-2, including victory back at Roland Garros six years ago. "I'm gonna just fight for every ball, and let's see," smiled Kasatkina.
But two days after the performances of their lives -- Gold Coast's Birrell downing women's fifth seed Jessica Pegula and Home Hill's Walton knocking out men's sixth seed Daniil Mevdevev -- their follow-ups fell flat.
Birrell was initially bamboozled and eventually outlasted by unorthodox Oleksandra Oliynykova, finishing with her 10th and 11th double faults as she folded in a 10-point tiebreak decider 6-3 0-6 7-6 (10-5).
Soon afterwards, Walton, whose edge was blunted after his five-set duel with Medvedev, was largely outclassed by American Zachary Svajda, who had beaten Alexei Popyrin in the previous round and again proved the Aussie slayer in a 6-3 6-4 6-7 (4-7) 6-2 win.
Just as against Pegula, the 28-year-old Gold Coast fighter Birrell produced a stirring fightback, but found the all-court, rhythm-breaking variety of the crafty Oliynykova too difficult a puzzle to crack.
Birrell appeared to have broken the code in the second set, latching onto the moon balls, drop shots and loopy slices to whitewash the increasingly weary-looking Ukrainian.
It proved an illusion. Oliynykova was still fresh and more solid in the decider, even daringly delivered an underarm serve on match point, winning it to prevail after nearly two-and-a-quarter hours.
Birrell still managed to raise a smile afterwards as she sighed: "Tennis is quite a roller-coaster sometimes, and you can have one of the best days of your life followed by one of the tougher, tougher days.
"But although today was tough, I'm still really proud of myself, the way I fought. I gotta keep my head up and keep moving forward, and remember all the good parts of this week when I've played some of the best tennis I've ever played."
Walton, too, had much to enthuse about after the biggest win of his career, but shrugged nothing had really changed for him.
"Like, I beat Medvedev, ate here, went back to the Airbnb, and did my nightly sudoku, and didn't do anything different whether I'd lost to him or beaten him," smiled Walton.
"I still went to bed the same person, and it doesn't change, doesn't change your life. Just went about my business as usual."
He did, he reported, manage to also solve the sudoku...
