Our pastor was invited once to speak about Christianity to the muslim student group on our college campus. He walked into an ambush -- it turns out that, without telling him, the student group also brought in one of Islam's foremost apologists (Jamal Badawi) to "debate" our pastor.
Our guy held his own well enough, but he wasn't nearly as polished (or as well prepared) as Badawi, and came across as the much weaker of the two.
Of course, God isn't limited by the shortcomings of His servants, so who knows -- perhaps some were intrigued by the Good News nonetheless.
I wonder if this guy would have the guts to go against Ravi Zacharias?