Nobody fills in like Gundo. I can't name another player past or present who's more intelligent than Gundogan on the pitch. He sees the things you should only be able to see with a birds eye view and slow mo replays at hand as they are happening infront of him and adjusts his game to give the team what it needs to function better at that moment, sometimes before even Pep sees it. Superb today.
I've said this before but it's worth repeating, he's going to be a superb manager if he wants to be when he hangs up his boots