Help vs Dark Eldar

I was wondering if anyone could help me with my problem...

A friend of mine fields the Dark Eldar and he basically has a perfect record against us. The only player that has been able to beat him is our Tyranid player. Now I imagine it was because of the Tyranids capabilities in melee but I'm not sure since I wasn't there. However, I witnessed my Chaos friend get creamed by the DE player in the first turn. The Chaos player was so wiped out he pretty much had to forfeit. :blackeye:

What is the best strategy to do against DE if you are a marine? I myself am a Blood Angel player. Honestly, I'm a little worried about getting into melee with him as I'm not 100% sure what all he is capable of. Is there a different approach I should look at when I fight against him next?

I even witnessed the DE player tear through my Space Wolf friend with a ton of AP 2 weapons..... I can't believe the Dark Eldar are able to field so much AP 2, it's almost unreal. :scratchhead:

He goes cheap in whatever he gets. I think his HQ might have cost him 300 points or so, but when it's all said and done he is still able to field 70 or more models. I usually see a Talos but I think he uses that mostly for bait. IDK, I guess I'm just curious on how other marines might play against the DArk Eldar is all.