Teenage triumph! 18 year-old Marta Kostyuk upsets the 2016 Roland Garros champion.
Garbine Muguruza is the latest big name to fall at the French Open as the night session descends on Paris with rising 18-year-old, Marta Kostyuk producing a straight sets win 6-1, 6-4.
A semi-finalist this year in Istanbul and third round at the US Open last year, it has been constant progression for Kostyuk and she has now taken the scalp of 2016 champion at Roland Garros.
It's a first top 20 win for her and Muguruza joins Naomi Osaka, Bianca Andreescu, Angelique Kerber, Jelena Ostapenko and Svetlana Kuznetsova in terms of Grand Slam champions to exit in the first two days with Serena Williams still to come.
This will also open up the quarter for reigning champion, Iga Swiatek with the highest seed now remaining being 22nd seed, Petra Martic.
Kostyuk had a superb first set handing Muguruza an uphill task and a 6-1 scoreline to boot as the 18-year-old Ukrainian dealt with the task in hand.
She had to deal though with a struggling Muguruza taking a MTO (medical timeout) during the set changeover which seemed to give the Spaniard an upward trajectory and break points.
But Kostyuk confounded that with a high looping forehand which just hit the line to hold her serve at 1-1.
With the threat of a potential break though, Muguruza dealt with it well with multiple unforced errors coming off the racquet of Kostyuk.
But it was Muguruza that produced the first break of the set going 3-1 up as she looked to level it up.
Kostyuk broke back though with Muguruza deemed to have her foot over the line when serving allowing the former a break opportunity and a forehand that went long gave her a 3-2 deficit.
From there, she swept her serve and pulled it back to 3-3 with Muguruza back struggling and the momentum swinging in her direction.
Muguruza was sending Kostyuk all around the court on her service game but it was one that the Ukrainian kept battling in as she pulled it from 40-0 down to break for a fourth time.
It was 12 out of 16 points from Kostyuk as she went one game away from knocking out the former World No.1.
Again, it was same story for Muguruza who lost her way from a good position on her serve with more unforced errors.
This allowed Kostyuk who had first match point but with her back against the wall, Muguruza produced three super points to save her skin and hold her serve.
Match point was brought up again as she brought the error from Muguruza to go 40-0 up and thriving at the task at hand.
A big backhand from the Spaniard gave her some time but she brought her to the net and Kostyuk hit across her to claim the big scalp.
Teenage triumph! 18 year-old Marta Kostyuk upsets the 2016 Roland Garros champion.