While we did show stupidity in defense, Cesc coming on highlighted one of the major improvements I've seen in the team under Martino: Playing with him really triggers the shift from our previously slow, almost glacial buildup to a quick and vertical based attacking style.
Even today, the difference looked so damn obvious. For the entire first half and some of the 2nd, our passing play was completely static and our players looked chained and tied to their positions with little motivation and fire (with the exception of Neymar). Later when we shifted to our attacking style to be more urgent, it was a frenzy of switching positions and linking up between Nemesis and Cesc. He was the key that unlocked the beast of our attack, bringing out the best of Messi who had previously been lethargic, and providing a perfect connection for Neymar as well.
Cesc is the way we're shifting to as we adapt to Tata. Xavi is the one that'll likely be slowed down, and that'll unchain our formation to become much more aggressive and fast paced in attack getting the best out of all of our players. It's been a while since we've looked as fluid and deadly as we have in the recent games with Fabregas.