10PM: Derek Stepan said on MSG, "watching the jumbotron you can't see any pucks crossing the goal line but Toronto said that they had a view. It's not a view that we saw. It was what it was and our group did a good job of responding."
9:10PM: At the start of the third period, John Giannone relayed a conversation that he had with Scott Arniel about the Capitals first goal and the explanation the Rangers were given.
Giannone said, "the NHL uses a system called Hawkeye where they have five different angles around the net and both teams have access and it's the one that Toronto uses to judge whether the puck is over the line. Apparently the Rangers system was not working at the time of that play with Jay Beagle in front so the Rangers have still not seen the puck cross the line but they were told that the Hawkeye system does show that the puck is over the line."
The official explanation from the NHL was At 10:58 of the second period in the Rangers/Capitals game, video review determined that the puck completely crossed the New York goal line. Good goal Washington.