FES, Morocco -- Former world No. 1 Dinara Safina and American teenager Melanie Oudin secured berths in Friday's quarterfinals at the $220,000 Moroccan Grand Prix tennis event.

Safina upended eighth-seeded Frenchwoman Alize Cornet 6-1, 6-3, while Oudin received a walkover into the round of eight when her scheduled second-round opponent, Slovenian Polona Hercog, withdrew from the field, citing a right ankle injury.

Up next for Safina, who's now 8-3 in her last 11 matches, will be fellow Russian Anastasia Pivovarova, while the 19-year-old Oudin will encounter Italian Alberta Brianti.

Pivovarova ousted second-seeded Yaroslava Shvedova of Kazakhstan 6-2, 7-6 (7-5), while Brianti downed Russian Ksenia Pervak 7-5, 6-2 on the red clay at the Fes Royal Tennis Club.

Friday's other quarterfinals will pit fourth-seeded Hungarian Greta Arn versus seventh-seeded Romanian Simona Halep and Belgian Kirsten Flipkens against 20- year-old Moroccan wild card Nadia Lalami.

The 2011 Fes champion will claim $37,000.