When you look at the replay from behind the play (from the end zone back line), you realize that the window was much narrower than it looks other wise. I'd say that the ball had about a 12" window because the defender actually made a good play on the ball.
And, BTW, one of the reasons that I am not a big Higbee fan any longer is that he is not steady on his feet (he doesn't run and cut with good balance) and he doesn't usually make the contested and difficult catch. He almost fell down TWICE on his route, which threw the timing off and made the entire play and throw well more difficult than it needed to be. The TD was entirely on Goff being patient and moving around well.