Linz, Austria - Top-ranked Victoria Azarenka reached the quarter-finals of the Generali Ladies by beating Simona Halep of Romania 6-1, 6-1 on Thursday.
Azarenka dominated play from the baseline and hit 20 winners.
Azarenka, who has only conceded four games in two matches, will next play either Petra Martic of Croatia or Patricia Mayr-Achleitner of Austria.
Bethanie Mattek-Sands reached her first quarter-final of the season by defeating Carla Suarez Navarro of Spain 6-3, 6-3.
The 201st-ranked American, who is battling her way back up the rankings after recent hip, back and left foot injuries, will face next face Irina-Camelia Begu of Romania.
Begu, who lost in qualifying but replaced Anna Tatishvili of Georgia in the main draw, beat Kiki Bertens of the Netherlands 6-4, 7-6 (9/7).
Results from the fourth day of the WTA Linz event on Thursday (x denotes seeding):
Victoria Azarenka (BLR x1) bt Simona Halep (ROM) 6-1, 6-1
Petra Martic (CRO) bt Patricia Mayr (AUT) 6-2, 3-6, 6-0
Irina Begu (ROM) bt Kiki Bertens (NED) 6-4, 7-6 (9/7)
Bethanie Mattek-Sands (USA) bt Carla Suarez (ESP) 6-3, 6-3