Copil, who won just three main-draw matches in the 2013 season, beat Simon 7-5, 6-3 with a break in each set in collecting his second victory of 2014. He won nearly three-quarters of the points on serve and fought off all four of the break opportunities Simon had.
Copil advances to the quarterfinals against Lleyton Hewitt, who knocked off No. 6-seed Feliciano Lopez by the same 7-5, 6-3 score. Hewitt had 11 aces and frustrated Lopez by winning nine of the 10 break points he faced. Lopes had eight aces but also committed eight double faults.
The other quarterfinal determined Thursday sends eighth-seeded Jeremy Chardy against Samuel Groth. Groth advanced by taking two tiebreakers from fourth-seeded Pierre-Hugues Herbert for a 4-6, 7-6 (7-3), 7-6 (7-5) victory while Chardy defeated Nicolas Mahut 7-5, 6-7 (4-7), 6-3 behind the only break of the third set.