The top seed is well backed by home support at the WTA International clay-court event, but the Romanian gave the partisan crowd a few nervy moments in an erratic second set.
Halep won 81 per cent of first-serve points in an opening set that the French Open finalist completely dominated.
However, the second saw an incredible seven breaks of serve and just three holds, the most crucial of which came when Halep served for the match at 5-4 to book a quarter-final tie with Lara Arruabarrena.
Second seed Roberta Vinci will also contest the quarter-finals, but only after coming from behind to defeat Silvia Soler-Espinosa.
The world number 24 landed just 53 per cent of first serves and was broken on three occasions, but she was comfortable in the final two sets of 3-6 6-2 6-1 success.
Vinci's Italian compatriot Karin Knapp had no such luck, however, as the fourth seed was shocked by Danka Kovinic, who is ranked 45 spots below her opponent.
Seventh seed Petra Cetkovska struggled, too, but the Czech eventually secured a 6-4 3-6 7-6 (7-4) success over qualifier Kiki Bertens.