Kohlschreiber finished strong for a 6-2, 1-6, 6-1 win over Benoit Paire. Kohlschreiber was solid in the opened set, getting a pair of breaks, but staggered in the second set and didn't manage a break-point chance versus Paire.
However, he rallied in the third set with two breaks in winning the final five games of the match.
He goes into a quarterfinals pairing against seventh-seeded Gael Monfils, who advanced with a 7-6 (7-4), 7-5 decision over Nicolas Mahut in an all-French second-round match. Monfils cashed in the only break in the second set to secure the victory.
Ivo Karlovic advanced when third-seeded Marcel Granollers retired in the second set. Karlovic was up 7-6 (7-3), 2-2 when play was stopped.
Fifth-seed Andreas Seppi sailed to a 6-2, 6-1 win over Vincent Millot and No. 8-seeded Nikolay Davydenko took out Gilles Muller 7-5, 6-4 while Jesse Levine was a 6-4, 3-6, 6-0 winner over Michael Berrer.
Top-seeded Jo-Wilfried Tsonga will go against Levine in the quarterfinals Friday while Davydenko takes on Karlovic. In addition to the Monfils-Kohlschreiber pairing, fourth-seeded Florian Mayer faces Seppi, in the lower half of the bracket.