It's difficult to see in real time and very subtle but I'll try to explain why Gus is the main one at fault on that goal. I don't have the time or desire at the moment to take screen shots and stuff but if you watch it back carefully you should see what I'm talking about.
Puck comes up the boards to Knies, everyone is in pretty good position. There's some spacing issues as Gio should have pushed up a bit and Gus should be a bit more inside but we're in decent shape. Knies loses it but at the moment the puck is turned over we're still in pretty good shape. Here's the mistake, the moment Knies loses it Gus needs to get back to the middle and stay on the right side of his man. Instead he stands and watches, only for a moment but as he watches Killorn jumps to the middle and goes to the net. Now he's on the wrong side of his man and Killorn easily beats him to the net. Giordano is in no man's land with 2 guys rushing at the net in front of him so he decides to try and front the puck, misses leaving two guys all alone for the juicy rebound.
On just about any goal or chance against there's multiple things that go wrong that contribute and rebound control and lost puck battle by Knies certainly fall into that category on this play. But the one play that took the situation from "we're ok" to "oh shit" was Gus being on the wrong side of his man. If he reacts quicker and is in position he boxes out Killorn making him a non factor, then Gio takes Stamkos.
I was just thinking of grabbing a Caesar
