Okay, so 1900 blitz really isn't that strong. If we were talking about 1600 vs. 2400, my advice would be to just play your normal game. But 1100 vs. 1900, your best chance might be to randomize the position with a weird set-up, hoping that he will forget the position of some piece or pawn. Something like the
https://en.wikipedia.org/wiki/Hippopotamus_Defence (if you're White just play 1.d3, 2.g3 etc.).
Given your difference in skill levels, if you start an open fight in the opening, it's likely that you will make some gross strategic blunder that your opponent will be able to exploit and get a dominant position very quickly. Your best bet is to play a closed set up and just try to stay in the game as long as possible hoping for a mistake.