Marta Kostyuk secures stunning upset as the Ukrainian 15th seed beats four-time champion Iga Swiatek in the fourth round of the 2026 French Open

The Ukrainian claimed her first ever victory over the Pole to secure a maiden appearance in the Roland-Garros quarter-finals.

Read more details and expert analysis in the piece below.

"I’m still in shock, you know. To beat such an unbelievable player who won four times here and I (always) lost to her before this, so, never taken a set off her...

"It’s incredible. I still can’t believe it. Thank you guys (the supporters in the crowd) for the energy today."

OPTA STAT: Kostyuk is the second player since the WTA Rankings were published in 1975 to win her first 16 clay court matches of the season while being ranked outside the top-10 (also Justine Henin in 2005).

The four-time champion, Iga Swiatek is OUT!

The 15th seed Marta Kostyuk remains unbeaten on clay in 2026 as she extends her winning streak to 16 matches.

The Ukrainian served out to 15 to claim a straight-sets win in one hour and 39 minutes to hand Iga just her fourth ever loss at Roland-Garros.

Kostyuk will now face Bencic or Svitolina in the last eight.

‘She’s lost the plot. She’s lost her game, the essence of what makes her great on clay,’ says Chris Evert on TNT Sports comms as the four-time champion offers up two more break points.

The Pole sizzles away a crosscourt backhand but thrashes a forehand long to leave herself on the brink.

Kostyuk turns to her team with a beaming smile and a clenched fist.

The Ukrainian defends magnificently before deploying the dropper, allowing Iga to charge forward and look for the put-away. The Pole makes a hash of it and the cat and mouse ends with the 15th seed edging the volley-off to move 30-0 to the good.

There’s no way back from there with Swiatek floating a backhand long to allow Kostyk to consolidate with a hold to love.

The four-time champion is on the ropes!

A wild forehand shows how rattled the Pole is right now and her 35th unforced error of the match tees up triple break point.

Kostyuk seals the deal on the first as she breaks to love with a thumping forehand up the line.

Kostyuk takes control at 30-15 with a lovely volley but Iga pegs her back with a superb backhand down the line, that she intelligently executes back-in-behind her opponent.

The Pole lands a sizzling return and makes it count with a thunderous inside-in winner but Marta staves it off with a clutch serve.

The Ukrainian wobbles with a poor volley into the net to offer up a second opportunity but Iga lets her off the hook with a wild, Hollywood backhand into the alley.

It develops into a real face-off around deuce with a double fault giving Swiatek a third chance that she again refuses to take with some over-zealous hitting.

The reprieves eventually see Marta claw her way out of dodge with a timely ace sealing a resilient and perhaps fortunate hold.

Once again Iga double faults at a key moment at 30-30 but this time she is ultra positive on the break point and fends it off with a crunching drive volley.

The Pole balloons a make-able forehand long to prolong her examination from deuce and then slips to allow Marta to earn another BP with a backhand down the line.

Sharp work at the net swats it away but a second double fault of the game coughs up a third chance and the Pole caves with shaky footwork leading to her sweeping a backhand wide.

Marta knows!

Swiatek returns from a lengthy spell off court between sets with renewed purpose.

The Pole probes at 15-30 and earns a couple of break points with a deep, looping crosscourt forehand that forces Kostyuk to snatch a strained response on the stretch into the net.

The third seed makes it count on the first of them with a thumping return down the line to give a timid second serve the treatment and get the four-time champion off to a flyer.

Marta is left rueing failing to make a backhand attempt down the line at 0-30 after Iga had double faulted to open the door.

The 15th seed sizzles a return long and looks to have missed the chance but another double fault from the Pole coughs up a set point.

Swiatek dictates trying to repel the danger but can’t breach her opponent’s defences and the Ukrainian conjures up a short, crosscourt pass from the backhand wing to clinch the break and a one-hour opener in style.

Marta double faults at 40-15 and on TNT Sports comms, Chris Evert wonders if it will be costly.

The Ukrainian loops a forehand wide to suggest it might but a shaky, poorly timed overhead slaps the tape and somehow drops over to put her back in charge at deuce.

Swiatek unloads on the forehand once again to tee up a routine bounce smash and keep the heat on but a clutch serve and a near miss on a second-serve return from Iga sees the 15th seed just about come through unscathed.

It’s another break!

Kostyuk makes an early statement of intent with a wonderful backhand return winner that licks the line.

Swiatek looks shaky and coughs up two break back points.

Marta stretches into an excellent, low crosscourt pass with the Pole advancing to the net and the third seed’s lack of confidence in the forecourt shows as she makes a mess of the volley.

‘Every point is good, every point is high quality in this match. They are both clubbing the ball!’

That’s the verdict of Chris Evert on TNT Sports comms as another exhilarating rally ends with Kostyuk thrashing a forehand way long to cough up two more break points.

It’s Iga’s turn to blink first on the next high-octane exchange and the Pole overcooks a crosscourt backhand shortly afterwards to allow Marta to get to deuce.

The Ukrainian lands a clutch serve to earn game point but arrows a backhand on the stretch into the alley and then offers up a fourth BP when Swiatek slams away an overhead.

Marta can’t find the first serve and Iga dictates off a sizzling return and forces the error with a deep, probing forehand.

Swiatek swats away a ball in dismay after a wild forehand flies off the island to allow Kostyuk to break back to love.

It’s a fine response from the 15th seed but Iga will be disappointing with how loose that game was having fought so hard to secure the advantage.

‘What! What a point,’ exclaims the legendary Chris Evert on TNT Sports comms.

It follows an onslaught of forehands from Iga as she battered away at Kostyuk’s backhand defence before finally dragging her to the right flank to steer a backhand winner to the opposite corner and secure the break.

Marta had looked in charge at 30-0 but a forehand flew a whisker long and Swiatek upped the ante from there.

Swiatek does most of the heavy-lifting with some bull-dozing forehands and leads us towards the business end of the set at three apiece courtesy of a hold to 30.

Marta puts together her best service game yet as she lands a succession of excellent first serves to cruise through a clean hold.

Swiatek gives herself extra work to do when she lashes a backhand down the line just long to allow a 40-15 lead to slip away.

Kostyuk is trying to be ultra-aggressive but it’s leading to some hasty errors.

The Ukrainian slams one make-able return right into the middle of the net to miss out on a chance to press for a break point and after a face-off around deuce she lets Iga off the hook with a mid-court forehand that also crumples into the net.