Top seed Gael Monfils fought from a set down to defeat compatriot Adrian Mannarino 4-6 6-4 6-1 in two hours.
This will be his fifth quarterfinal appearance in Montpellier, as the World No.9 triumphed here on two occasions (2010, 2014). After falling to Dominic Thiem in the fourth round of the Australian Open, the charismatic Frenchman hopes to right the ship and win his first title since Rotterdam (2019).
Monfils will face Slovakian Norbert Gombos for a spot in the semifinals. The World No.108 defeated Norwegian Emil Ruusuvuori 7-5 6-4 in an hour and 12 minutes.
Richard Gasquet defeated veteran Spaniard Feliciano Lopez 6-7(1) 6-4 6-2. He will meet Canadian Vasek Pospisil for a spot in the semifinals.
France's Pierre-Hugues Herbert pulled off the day's upset, defeating fifth seed Felix Auger-Aliassime 7-6(2) 7-5. He will face David Goffin, as the second seed saved five set points to overcome Kazakhstan's Alexander Bublik 6-3 7-6(9).
Rounding out the quarterfinalists is Serbian Filip Krajinovic, who breezed past Sweden's Mikael Ymer 6-1 6-1 in an hour and 18 minutes. The seventh seed meets unseeded Frenchman Gregoire Barrere, who upset fourth seed Grigor Dimitrov in the previous round.