860 supporters had to endure a scoreless 30 mins as Lion's goalie Aaron Mallet turned away everything the Racers could throw at him. But Haringey finally broke the deadlock midway through the second period when Mason Webster was teed up by Ricky Rutherford (in photo) and Lee Mercer.
The Racers then doubled the lead just over a minute later when the red hot Sean Martin scored unassisted while Haringey were shorthanded.
Haringey made sure in the final period when Matt Brown was set up by Jack Cooper and Ben Osborne and Rutherford added an unassisted fourth.
The Lions grabbed a late consolation goal in the final two minutes, when Vas Fedotovas scored on the powerplay and denied Haringey goalie Ian Shepherd a 27 shot shutout on his return from injury.
Racers coach Dan Sampson says: "We got the job done, but it wasn't us at our best at all. We battled, though, and got our rewards in the end. Ian Shepherd made some very important saves and was unlucky not to get what would have been a well deserved shutout.
"Our discipline was poor again, which has been a recurring problem this season. We got away with it against Lee Valley but other teams will use it against us and we can't afford to take the chance.
"It was great to play in front of a big crowd again and hopefully that will continue. It was also great to claim the bragging rights and I hope to see many tough battles from this derby fixture in the future."
The Racers will now turn their attention to a must win cup game away at Chelmsford Warriors on Saturday (March 22nd) and Sampson adds: "We'd love to win the cup and pick up some silverware in our first season and we know that when we play five on five no one can touch us. We all need to turn up on Saturday and play to our potential.
"We've had some good games against Chelmsford already and they are a hardworking, talented young side. But we set the bar very high for ourselves a couple of weeks back and we are looking to push that level even higher."