I reckon Palace will win it.
United will look to dominate possession, which will suit Palace. They're a very good counter attacking team.
United's full backs are probably their weakest position, right up against Palace's strengths in Bolasie & Zaha. That's really where I feel the game will be won and lost. If United's full backs can handle Bolasie & Zaha, then United will win. But I don't think they will, I've not been impressed with any of United's full backs all season.
I also think in a one-off game Pardew can be very, very good tactically.
Going for a 2-1 Palace win.