Third-seeded Borna Coric advanced to the Grand Prix Hassan II quarterfinals on Wednesday with a walkover after Italian opponent Simone Bolelli withdrew with a left-knee injury.
The 19-year-old Croat next faces veteran Paul-Henri Mathieu after the 34-year-old Frenchman beat Maximo Gonzalez 7-6 (4), 6-0, breaking the Argentine's serve four times.
Coric and Mathieu have never played each other before.
Meanwhile, Argentine Facundo Bagnis also reached the last eight after upsetting second-seeded Joao Sousa 6-2, 6-4, breaking the Portuguese player's serve five times.
Bagnis next faces former runner-up Albert Montanes, who advanced with a 6-4, 6-4 win against fellow Spaniard Daniel Gimeno-Traver.
In remaining first-round play, No. 7 Pablo Carreno Busta of Spain had five aces in a 6-2, 6-3 win against Evgeny Donskoy of Russia.