the 3rd seeded Andy Murray yesterday in the quarterfinals 6-2, 2-6, 6-3.
Monfils, who at 6 feet 4 inches tall is three inches taller than the 6 feet 1 inch tall, 29 years old Federer, will look to solve the Federer puzzle as the Frenchman is 0-5 lifetime in the matchup.
Federer will also enter the semifinal with an eleven match winning streak, having won ATP Tour titles this fall indoors in Stockholm, Sweden and Basel, Switzerland.
The two players have never met indoors before and in their last meeting at the 2009 French Open quarterfinals, Federer won 7-6(8-6), 6-2, 6-4.
After his lone grand slam victory this year in January at the Australian Open, Federer lost an uncharacteristic nine ATP Tour tournaments in a row.
But with Federerís confidence soaring throughout the fast indoor season, Monfils will need to a mix masterful aggression with a determined patience in order to stand any sort of chance.
In the first semifinal of the day with play beginning at 2:00pm Paris time, Franceís second hope of the tournament, the unseeded Michael Llodra takes on the big serving and 4th seeded Swede Robin Soderling. Head to head, the 34th ranked Frenchmen surprisingly leads the 5th ranked Soderling 2-0.
This year marks the first time ever two Frenchmen have reached the tournamentís semifinal round.