It's 6 hours if you drive yourself. But taking a car to NYC is not an inexpensive or wise thing to do. Finding a place to park and keep your car without paying an arm and a leg is very hard. Most people fly or take Megabus. And if you take the earliest Megabus on 12/26 at 6am.... you get to midtown manhattan at 2:05pm. Then checking into hotel (got to have a place to put your stuff) and then catching the subway to the bronx makes it a real tight fit to try to get to the game by kickoff.
it can be done..... but a 7pm game would be much easier.
The other option is to take the 10pm Megabus on Christmas night and get to midtown manhattan at 6:35am. Then, assuming you have early checkin at your hotel, you can relax and have no issues making it to the game on time. If I go, this is probably the way I'll do it. Sleep all night on the bus, have the day in NYC prior to the game to relax and enjoy things.
Or fly in.
