Latvia has a first female semi-finalist at a major after Jelena Ostapenko beat Caroline Wozniacki two days before her birthday.
Kristina Mladenovic eliminated defending champion Garbine Muguruza but will not feature in the semi-finals after defeat to Timea Bacsinszky.
Poor weather at Roland Garros has led to the schedule being altered, with all four men's quarter-finals now set for Wednesday.
Changes to the format of the Davis Cup have been approved by the ITF board, with an AGM set to determine whether they will be introduced.
Andre Agassi has only just started to coach Novak Djokovic, but Goran Ivanisevic said: "I don't think it's going to last."
Though he needed treatment in his fourth-round match at Roland Garros, Stan Wawrinka is not concerned by his back problem.
Simona Halep enhanced her status as favourite for the French Open, while Caroline Garcia prevailed in her grudge match with Alize Cornet.
Caroline Garcia awaits Karolina Pliskova in the French Open quarter-finals after the second seed battled back to beat Veronica Cepede Royg.
Gael Monfils showcased more of his trademark agility on day nine at Roland Garros, while Petra Martic has an alcoholic tipple in her sights.
Should they meet at Roland Garros, Novak Djokovic is capable of halting the clay renaissance of Rafael Nadal, according to Andre Agassi.