Aidy Boothroyd made his discontent with the match officials clear as the Cobblers’ winning streak was ended by Oxford United.
The Us ran out 2-1 winners at the Kassam Stadium despite a third goal of the season for Clive Platt and a spirited midfield performance - against his former club - by Chris Hackett.
James Constable and substitute Jon-Paul Pittman scored the goals for the home side that leave Northampton 10th in npower League Two with the gap to the top seven still only two points.
But Boothroyd was not happy with both the Oxford goals, with both players appearing to be in offside positions when they scored.
“I thought the linesman made a few mistakes,” he said. “I’m not sure if the second one was offside but at the time it felt like it was.
“The first one did too. It’s very difficult because nobody means to get something wrong but they did on this occasion.
“The ball was played down the line and it was a clear four yards out. It nearly hit the dug-outs. That’s not good enough.”
But despite the dubious nature of the goals, the case could be argued that Oxford deserved the victory - they hit the woodwork twice and although Northampton had a lot of possession, Ryan Clarke was not an overworked figure in the home side’s goal.
Boothroyd felt his side could have got the ball into the danger zone more than they did, and conceded an inability to do so was a factor in the game’s outcome.
“They started much better than we did and I think that is because they’re a wounded animal and because they haven’t been getting the results they should be getting,” he said.
“I knew they were going to come flying out at us, which they did. They surprised us with a couple of things they did at set-pieces and we didn’t really deal with that well enough as a team.
“We weathered a storm and got back in the game; you know against a side like Oxford that the crowd can either work for them or against them and they were just starting to turn after we scored.
“Perhaps we should have got the ball in the box a little bit more because when we did that we seemed to get chances.”