One would need to demonstrate to them that there was prophecy of God coming in the form of man and that Jesus fulfilled the prophecies made concerning that.
In the link below about 1/4 the way down there begins a list of messianic prophecies and the fulfillment thereof. I'd copy paste the chart but the forum doesn't hold columns and it would be a jumbled mess.
http://www.jesus-is-lord.com/messiah.htm
I would imagine that the only ones that would be of major importance upfront would be any that deal with the manner in which the messiah would come and Jesus' fulfillment of those. There isn't much in the NT that you could use that would impress him except to demonstrate that Jesus fulfilled an OT prophecy. You're going to have to come at this using the OT.