While, he's putting up a lightscreen use Psych Up and copy all the calm minds and attack raised. Then you should have a Calm mind against the confusion and be able to take down the lightscreen in one blow, with all your boosted power. So take it down (and maybe even Yuki) with a Shadowball, then finish it up with a Hyperbeam and send him to the pokeball. The Hyperbeam will stop his mental concentration for psychic.

Psych Up ~ Shadowball ~ Hyperbeam