Been there, done that.
In my experience, the only way to consistently defeat the Phoenix is Ironhand's tactics against Aim-120 with a slight modification. In case you have no idea what I am talking about, watch this:
In order to defeat the Phoenix, you'll need to turn your nose slightly away from the oncoming radar and pitch down slightly as early as possible - either from the moment your RWS detects a radar signal, or the moment you see a missile track coming at you from very far away (>75 km), which is the signature of a Phoenix launching. Do not wait until the radar on board the missile locks onto you. That as far as I can recall is a very dangerous thing to do. The rest is the same as shiwn in Ironhand's tutorial.