Second seed Venus Williams overcame a slow start to see off Fabiola Zuluaga in the J&S Cup in Warsaw.
The American, who won her first tournament for 14 months a fortnight ago, beat the Colombian 4-6 6-2 6-0 to reach the third round.
There she will play either Patty Schnyder of Switzerland or Manuela Maleeva of Bulgaria.
Eighth seed Anna Smashnova-Pistolesi beat former top-10 player Daniela Hantuchova 6-4 7-5.
"It was a really good match for me," said Williams.
"I think she was returning my serve well, even when I was getting some good first
serves in.
"I didn't get as many service winners or easy points off my serve as normal, but my first serve was more consistent in the second and third sets."
Top seed and defending champion Amelie Mauresmo will face Eleni Daniilidou in the second round on Thursday.