Taipei - Venus Williams beat Poland's Urszula Radwanska 6-4, 6-2 to set up a Taiwan Open quarter-final against Anastasija Sevastova, despite not hitting top form on Thursday.
The top seed was broken in each set but she still had too much for Radwanska, ranked 101 places lower at 113th in the world, as she went through in 86 minutes.
The seven-time Grand Slam winner, 35, sent down two double faults and only landed 48 percent of her first serves in the first set but reached her debut quarter-final of 2016.
Next up for Williams is a first career meeting with Latvia's Sevastova, also ranked outside the top 100 at 103, as she eyes her 49th tournament victory.
Local hope Hsieh Su-wei beat Mandy Minella 6-4, 4-6, 6-2 to join Williams in the last eight alongside fellow seed Misaki Doi of Japan, who ousted Magda Linette 6-2, 6-3.