Snow flurries and blustery conditions greeted the players at the outdoor tournament. Dementieva and her opponent Meilen Tu, both wore pants and long sleeves during their match.
Tu warmed up first and took the opening set in a 7-5 tiebreaker, but Dementieva, seeded seventh in Warsaw, evened the match with a 6-0 second-set win and advanced by winning the third set, 7-5.
Anna-Lena Groenefeld won the right to meet world No. 1 Justine Henin in the second round with a 6-2, 6-4 win over Kaia Kanepi. Defending Warsaw champion and No. 2 seeded Kim Clijsters will face local favorite Agnieszka Radwanska, who advanced with a win Tuesday.
A much-awaited match pitting unseeded Venus Williams and Michaella Krajicek was postponed until Wednesday because of darkness.