World No. 1 Novak Djokovic stormed into the semifinals of the Geneva Open, beating Dutchman Tallon Griekspoor 7-5, 6-1 on Thursday.

Djokovic saw off a first set challenge from Griekspoor to win in 77 minutes.

Griekspoor, the world number 27, was the sixth seed at the 28-man Geneva tournament, which serves as a warm-up before next week's French Open.

Djokovic will face Tomas Machac of the Czech Republic, who defeated American Alex Michelsen 6-3, 7-6(2), in the semi-finals on Friday.

In Thursday's other matches, second-seeded Casper Ruud of Norway edged off Sebastian Baez of Argentina 6-3, 3-6, 6-4, while Flavio Cobolli of Italy crushed Alexander Shevcheno of Kazakhstan 6-4, 6-4.