Bammer was playing her third match in four days. The Austrian won the Pattaya Open in Bangkok on Sunday and then played in the first round in Antwerp on Tuesday.
Bammer still fought off five match points before finally giving in to fatigue and her Russian opponent, reports AP.
In the first round, eighth-seeded Ana Ivanovic of Serbia beat Anastasiya Yakimova of Belarus 6-3, 6-2.
Two-time defending champion Amelie Mauresmo opens her campaign for the diamond racket trophy on Thursday. If the top-seeded Frenchwoman wins the tournament this week, she get to keep the gold and gem-encrusted racket.
Kim Clijsters, who is in her farewell season and has overcome a sore hip and a cold, plays Olga Poutchkova of Russia to start her last home tournament late Wednesday.