Argentina's Del Potro reached his second consecutive Rotterdam final with a 6-4, 6-4 decision over Grigor Dimitrov of Bulgaria.
The former U.S. Open champion will be seeking his 14th career title Sunday. He fell to Roger Federer in last year's championship tilt.
His opponent will be Benneteau, who upset Federer in Friday's quarterfinals and followed that up Saturday with a 6-4, 7-6 (7-2) win over fifth-seeded Gilles Simon.
The Frenchman will be looking to land his first-ever ATP Tour title.