Preventing an eventual checkmate

Tonight I played someone who was good in an online chess tournament and my opponent was about to get a eventual checkmate, but I pinned black's queen preventing it and won!

My opponent let his clock run out instead of resigning because he knew the outcome, but he would have had enough time to checkmate me had I not moved bishop to d3 queen at that moment? I looked up his username and it's German for an AI institute in Brussels?