Cobblers boss Justin Edinburgh was left upset with the 'bizarre' decision not to award his side a last-gasp penalty in their 1-0 defeat to Shrewsbury Town on Saturday.
Moments after Lenell John-Lewis put Shrewsbury into a late lead, Chris Long was seemingly felled inside the penalty area but only a free-kick was awarded.
That upset both the players and Edinburgh at the time, and with the subsequent free-kick coming to nothing, followed by the full-time whistle, the Town manager's frustration was still evident post-match.
"I'm disappointed to be standing here talking about a major decision first game in," he said.
"The simple fact is that it's a stonewall penalty. The referee's in a good position because he's given the free-kick. It's quite clear-cut but he's made the wrong decision.
"There were appeals for them (earlier on) but obviously the referee dealt with that because it was a blatant dive from their player (Abu Ogogo), but if he hasn't given the free-kick then there's no decision.
"But he gave the free-kick and it's quite clear that Chris Long is in the box. He doesn't even get over the line so it's just bizarre to see how he's actually awarded the free-kick. It's in the box.
"I'll speak with him now and see what his views are but I've seen it and it was a poor decision."
Nevertheless, Northampton could have few complaints at the final scoreline after a disappointing performance.
Shrewsbury dominated the first-half and though the visitors came more into the game in the second, John-Lewis' goal two minutes into added time condemned Edinburgh's new-look team to an opening-day defeat.
He added: "Obviously I'm disappointed with the outcome. Defensively I thought we were good but there's a lot of work to be done in possession for sure because we weren't at our best with the ball.
"But defensively we were value for the point and unfortunately we haven't been able to see that through.
"We'll reflect and we'll be reasonably satisfied with our defensive shape and our work-rate but we're disappointed with the amount of possession that we lost throughout the game and that's what cost us.
"It's disappointing to take but we have to move on and go again."