Tottenham's leading scorer Les Ferdinand scored both of Newcastle's goals the last time they won at White Hart Lane, way back in 1996, and although he was injured and unable to play against his old club his replacement opened the scoring.
Iversen drilled home after Ledley King's shot from Darren Anderton's corner was half-cleared by Nolberto Solano.
There was a scare for Tottenham in the 31st minute when Bellamy latched on to Dean Richards' attempted header back to Neil Sullivan and forced the goalkeeper to save with his legs.
Bellamy then dragged a shot wide before Iversen threatened again - the Norwegian forcing a save from Shay Given.
For Tottenham the thrashing meant there was to be no honeymoon after their stunning Worthington Cup thrashing of neighbours Chelsea.
Newcastle, meanwhile, would have been thrilled to win again in London.
After going four years without a win in the capital Robson's men beat Arsenal at Highbury in December and now they have made it two out of two in the capital.