My advice try to do a rematch against him using the same army and approx the same terrain. This time around use the heavie armour, as they are all but immune to most of the spells of denegra. (it's the debuffs that get you...) Sorsha should be kept back a bit unitl the time arives to jump her forward, feat, and windrush to safety. All the other focus can be used to let the jugger and destroyer destroy things...
As a final tip I would like to advice against the mortar and take a manhunter instead. more reliable to get the kill
IMHO...
Do with the advice as you please, because I do not mind you lozing to cryx