So my regular opponent is a Tau player who regularly pulls a tactic that devastates at least 1 squad every round of shooting and I have a difficult time fighting back when it happens.

So I'm playing Dark Angels Greenwing (Already not looking good against Tau) and what usually happens, is that around turn 3, when space in my deployment zone opens up he drops in his Battlesuits running full plasma and full drones as a defensive screen. Due to his pact with some sort of Luck Daemon, he often never rolls scatter (I've checked it's not loaded. (Unfortunately, as that would explain his preternatural luck!)) and they plonk down unleashing something like 18 pulse carbine shots and 15 plasma rifle shots often enough to rip apart 1 10 man tactical squad (I run high tactical squads) and then jump away and then come back and do it all over again. As he does it on deep strike, I've got no response for this and I've yet to eliminate his commander.

I'm often trying to win the game through objectives and he's often trying to wipe me off the table and ignore the objectives.

It would be going a lot better for me against him if I could fight back against that one move he makes against me and the only way I can really fight back is to have him roll on the deep strike mishap chart OR keep all of my forces back in defence of my deployment zone and let him capture objectives.

Clearly neither of those are good moves.

I beseech you hive mind, little help?