Superb 1st half from him, to show he's hasn't been bad because of the system. Hopefully he keeps such form until the end of the season.
It's *exactly* that he's been "invisible" because of the system. Barça is flooding the midfield and playing short quick passes today (a.k.a. "tiki-taka")- *including* Neymar, who has stopped the ball-holding that killed play down the left (yes, Neymar 2.0, keep it up!). Messi is all over the place, including playing 1-2s with Iniesta & Company over on the left.
We've only seen this Barça occasionally this season. He's sure to play his more defensive role again when required, or when the starting roster demands it of him.