Defending champion Rafael Nadal reached a record-extending 14th French Open semi-final after outlasting Argentina's Diego Schwartzman in a tricky battle played in front of 5,000 fans in Paris.
Nadal, 35, will face the winner of Serbian top seed Novak Djokovic or Italian ninth seed Matteo Berrettini.
The pair meet on Chatrier at 19:00 BST.
Djokovic, 34, avoided a shock fourth-round exit when he fought back from two sets down against teenager Lorenzo Musetti, leading 6-7 (7-9) 6-7 (2-7) 6-1 6-0 4-0 when the 19-year-old Italian retired.
Berrettini, 25, has not played since Saturday after he was given a walkover following Roger Federer's withdrawal.