The Baggies youngster was unlucky to be on the losing side at Gillingham on Saturday in a game that Johnson felt his team 'should have won' let alone ended up going home with even a point to their name.
"Berahino took his goals very well and he is doing a good job for us," Johnson told the official club website.
Northampton now prepare for a tough FA Cup fixture at Luton next weekend with a good result going some way to lift the gloom at Sixfeilds that comes with the club's poor league position.