Magda Linette caused the first big shock of the French Open on Sunday with a three-set win over the sixth seed Ons Jabeur.
Jabeur, 26, entered the tournament as one of the favourites on the back of her victory at the Madrid Open.
She won the first set 6-3 and led 3-1 in the tie break in the second set.
But the 30-year-old Pole claimed the shootout and secured an early break in the decider.
And she showed fortitude to keep her composure after squandering her advantage.
She took it 7-5 after Jabeur fluffed two chances to force the match into the new final set super tiebreaker.
Skill
"She didn't give me too many options and I felt that she had an answer to all my shots," said Jabeur who reached the final at the Italian Open last week.
"She played very well in the important moments."
Linette, who lost to Jabeur in the third round at last year's French Open, said: "I've seen how well Ons has been playing so I knew I had to be focused and try to make her uncomfortable. I'm just happy I managed to fight for every single point."
Former champion Garbine Muguruza was another high profile casualty in the women's draw.
The Spaniard, who beat Serena Williams to claim the 2016 crown, lost in three sets to 36-year-old Kaia Kanepi from Estonia.
Return
Men's ninth seed Felix Auger-Aliassime was all at sea for the first 85 minutes of his match against the Peruvian qualifier Juan Pablo Varillas who swept into a 6-2, 6-2 lead.
The 21-year-old Canadian, making his first appearance on centre court, struggled with Varillas' pace and variation.
He managed to take his opponent's serve for the first time at the start of the third set and began his way back.
"He was playing well and very fast," said Auger-Aliassime. "I had to get a few tricks out to give myself more space and time. I was able to do so and it was easier towards the end."
