Of course, the Rangers and the immediately wanted it waived off for a high stick, so the referees went to Toronto for a review. After a somewhat lengthy review, the call on the ice (which was a good goal) would stand, and Pittsburgh would take a 2-1 lead.
At first look, it does look like a high-stick, but on the one camera angle, you can see that the puck makes contact a little further down Guentzel's stick. The part that hits is below the crossbar, and even though the blade of his stick is over the crossbar, the referees got the right call on the play.