I dont really play SP, but have you tried looking at some videos of people playing the level?
Perhaps you can get some tips and tricks from that? https://www.youtube.com/watch?v=In1yCsy0i1Ihttps://www.youtube.com/watch?v=F7MnzeVgBQA
One thing the created of the level pointed out in forums earlier:
One of the reasons this level might seem hard, is due to the fact that on the original single player path levels you could play defensively and still get a win. On this level you must play aggressively, you have to focus on breaking up enemy bonuses. You must also be quick, since the enemy team will play a sanction card on you around turn 16.