On this performance Wimbledon's manager Stuart Murdoch will have some work to do on the training ground as the Dons failed to take any control of this game.
The visitors first and best chance came in the eighth minute when ex-Forest striker Neil Shipperley played a neat one-two on the edge of the box with Jermaine Darlington whose final shot beat the Forest keeper but sailed inches wide.
Forest's first goal came in the 16th minute when Riccardo Scimeca chipped the Dons defence and the ever vigilant Johnson was on to the ball like lightning and chipped the advancing keeper Kelvin Davis.
Ten minutes later the visitors went close with a free-kick 20 yards out, but Joel McAnuff's shot took a slight deflection from the five-man Forest wall and was comfortably saved by Darren Ward.
On the stroke of half-time it was Johnson who doubled the Forest lead. This time the ball was supplied by Jim Brennan who crossed from the right and Johnson's header from ten yards out left the Dons keeper with no chance.
The game failed to flow with the referee's whistle constantly in play.
Forest shut up shop in the second half with some excellent defending led by captain Des Walker. Murdoch tried in desperation to save the match replacing Par Karlsson and Shipperley with Gareth Ainsworth and Adam Nowland midway through the second half but this was to no avail.
Wimbledon's frustration showed and they now must head back down the M1 empty handed.
This will be a long hard season for Wimbledon if they don't improve their game and fitness. Forest can only grow in confidence from this win as they find themselves in the top half of Nationwide Division One.