Iain Dowie watched his Oldham team cruise to one of their biggest wins of the season and then attacked the performance.
Dowie was unhappy that struggling Northampton were allowed to stay in with a shout until veteran winger David Eyres scored Oldham's third with 19 minutes to go.
He said: "We were no where near the right standard in terms of defensive solidity or passing and movement, so we gave Northampton a chance.
"We cut loose toward the end when they had to push forward but until then our discipline was not good enough.
"The plus point is that we won 4-0 without playing as well as we should. The scoreline probably flattered us, but some of our finishing was superb." Stunned Cobblers boss Kevan Broadhurst couldn't believe what he had seen, insisting: "We had absolutely no luck and my players are sat in the dressing room bewildered.
"I asked them for a big effort tonight because we have been under pressure but when you are down there things just don't go for you." The game began quietly as neither side could find their passing range, but Oldham sprung to life after 28 minutes.
Midfielder Darren Sheridan delivered a low cross from the left and Wayne Andrews swept in his fourth goal of the season with a cool finish from 12 yards.
Jamie Forrester wasted a couple of half chances for Northampton before the home side doubled their lead just after the hour.
Josh Low charged down the right and crossed to the far post, Eyres nodded back into the six yard box and former Northampton striker Carlo Corazzin had an easy tap-in.
Northampton had to go for it and they almost replied when Marco Gabbiadini's header was cleared off the line, but Eyres converted his penalty after Richard Hope sent Andrews crashing.
The best goal came from midfielder John Eyre with nine minutes left. Running on to a pass from Chris Killen he stroked a perfectly hit shot into the bottom corner from 20 yards