Tasaka had the first real chance to open the scoring for Bochum after 15 minutes, but the midfielder could only fire his effort high and wide of Brad Guzan's crossbar.
Villa's best chance arrived late in the half when Westwood found Weimann in the box, but the Austrian international could only slide a low effort wide of the post from a promising position.
Villa continued to dominate as the second period gathered pace, with Bacuna and Marc Albrighton both curling efforts just high of the crossbar from outside the box.
It might have been more than 2-0 for the away side in the latter stages with Bacuna and Helenius both coming close, but it was the German outfit who ended on a happier note late on courtesy of a curling strike from Tasaka. body check tags ::