The hosts began on an attacking note unleashing back-to-back forays in their opponent's citadel. But a valiant Army goalkeeper KU Zaman denied them results for a long time.
In the 14th minute, Sunil Sharma's effort was brilliantly saved by Zaman and four minutes later he again fisted away another goal-bound header by Ajay Kumar.
However, Zaman's efforts could not save his team for a long time as in the 36th minute, Kumar succeeded in finding the target and put the Bihar outfit into the lead.
Bihar, regrouped and in the 58th minute found the target for the second time with Sunil scoring.
Railway Coach Factory, Kapporthala will meet SSC Manipur, while Southern Samity (Kolkata) will clash with Mizoram XI tomorrow in the quarterfinals knockout matches.