Simon next faces eighth-seeded Benoit Paire in an all-French match, while Llodra plays Jan Hajek of the Czech Republic — who led 6-0, 4-2 against seventh-seeded Viktor Troicki when the Serb retired from their match.
“He impressed me earlier,” Llodra said of Hajek. “The match is within my reach, but all of these matches are tough.”
Sergiy Stakhovsky also advanced by beating Tatsuma Ito of Japan 6-7 (4/7), 6-4, 7-6 (7/3) and the Ukrainian will face Jarkko Nieminen of Finland.
Third-seeded Richard Gasquet will meet No. 6 Julien Benneteau in another all-French match after coming back from an error-strewn second set to beat compatriot Gael Monfils 6-3, 2-6, 6-3.
Benneteau cruised into the quarter-finals, taking little over an hour to defeat Victor Hanescu of Romania 6-4, 6-4.
Top-seeded Marin Cilic of Croatia moved a step closer to a third title in his home event, beating Grega Zemlja of Slovenia 6-3, 6-2 on Thursday to reach the quarter-finals of the Zagreb Indoors.
Cilic won this tournament in 2009 and 2010 and improved his record at the event to 14-4. He hit 11 aces and broke his opponent three times to wrap up the win in 1 hour, 6 minutes.
“I am very pleased with the way I played,” Cilic said. “I felt he was nervous in the beginning and it helped me gain an early advantage.”
Cilic will face another Slovenian, Blaz Kavcic, who rallied to upset sixth-seeded Marcos Baghdatis of Cyprus 3-6, 7-6 (7/2), 6-4 and reach his third career quarter-final.
Baghdatis, the 2007 champion, failed to serve out the match at 5-4 in the second set, and then pulled out of the doubles because of a foot injury.
“I did not want to take any risks,” he said.
Ivan Dodig also reached the quarter-finals by defeating fellow Croat Ivo Karlovic 7-6 (7/2), 6-7 (2/7), 6-3. Dodig wasted a match point at 5-4 in the second set, allowing Karlovic his only break.
Dodig was to play defending champion Mikhail Youzhny yesterday.
Fourth-seeded Jurgen Melzer of Austria also came from a set down to defeat Somdev Devvarman of India 1-6, 7-6 (7/5), 6-2. Devvarman had a 5-3 lead in the tiebreaker, but then lost four points in a row. Robin Haase of the Netherlands defeated fifth-seeded Martin Klizan of Slovakia 6-2, 4-6, 6-4.
Also on Thursday, Lukas Rosol of the Czech Republic ousted Italy’s Flavio Cipolla 6-4, 2-6, 6-3 and Philipp Petzchner of Germany beat Croatian wild-card Dino Marcan 6-3, 6-4. Marcan entered the tournament as a replacement for second-seeded Andreas Seppi, who withdrew because of an illness.