Defending champion Iga Swiatek was sent packing from the French Open by Greek world No.18 Maria Sakkari, who stunned the 20-year-old Polish star 6-4, 6-4 and set up a semi-final clash against Czech Republic's Barbora Krejcikova.World No.33 Barbora ended American teenager Coco Gauff's hopes of reaching her maiden Grand Slam semi-final with a 7-6 (8-6), 6-3 victory.Maria, who is now the highest-ranked player in the field, is just two wins away from a historic maiden Grand Slam singles title for a Greek woman. A win at the end of the week could also propel her into the top 10.Iga was on a winning streak of 11 matches and 22 sets at the Roland Garros, but a right thigh strain seemed to be bothering her all through the match against Maria.Coco had been in great form on clay and cruised to her maiden Grand Slam quarter-final with ease but on Wednesday she was unable to take any of the five set points in the opening set and simply faded away.The 17-year-old led 3-0 and 5-3 in the opening set, as well as 6-4 in the tie-break, but each time Barbora clawed back.The disappointment after the missed set-points for Coco was evident as she made a poor start to the second set. Coco's pent-up frustration came to the fore when she smashed her racquet after a double fault that left her 4-0 behind.Barbora, better known for her doubles exploits -- she was ranked world No. 1 in 2018 and has won two women's doubles and three mixed doubles Grand Slam titles -- showed no sign of nerves as Coco self-destructed.