The second-seeded Frenchman won his 16th match in a row at this tournament with a routine 6-1 7-5 triumph over Daniel Brands and next faces surprise package Lukas Rosol.
"It was a perfect start for me," Simon said on atpworldtour.com.
"I was serving well and returning most of the time and playing good from the baseline. I didn't miss any easy shots in the first four games.
"Then I got a little bit tight and played more defensive. I lost my serve at the very beginning of the second set and I knew I had to be more aggressive. I'm happy with the way I finished the match."
Rosol is through to the last four of an ATP event for the first time.
The Czech beat third seed Andreas Seppi en route to Friday's last-eight meeting with Viktor Troicki, and again looked in good shape as he ousted the eighth seed 6-3 6-1.
Top seed Janko Tipsarevic of Serbia crashed out as he succumbed to a 6-3 3-6 6-4 reverse to Spain's Guillermo Garcia-Lopez.
Garcia-Lopez, the world number 87, next faces fifth seed Florian Mayer, who ousted home hope Victor Hanescu 6-3 7-6 (7/3).