Tau V Eldar 2k the scouring loss

This was my first time playing Eldar and all I really knew about them is that they are very mobile and have tonne of psychic powers than can really screw with an army. I lost my Riptide from some psychic power that caused it to hurt itself. My opponent used a wraith army which had a majority of toughness 6 and all bar 1 model had a 3+ save. Once I killed off the HQ I was able to rip the wraiths apart with my AP 1 & 2 heavy army. I didn't really take note of who killed who and what moved where. It was looking at a very close win after I killed off his 20 wraiths but a unit of striking scorpions were camping in some terrain and took a huge amount of fire to kill them off but 2 remained and my opponent won, barely. I made a few tactical mistakes but if I hadn't taken them I may have lost an objective.