Defeat at the One Call Stadium left Town without a point or a goal on their travels this season but Cox said: "I don't think Northampton are a bad side and I can still see them being well up there later in the season.
"They are very hard to play against and probably a tweak away from being a top side. They just need something to click for them like we had last season."
Aidy Boothroyd again felt that the rub of the green was against his side but promised that they would not just wait for a change of fortune to see them move up the League Two table.
"When things don't go for you, you redouble your efforts and work twice as hard," he said.
"So we will be in tomorrow (Sunday) all day and every day and we will work twice as hard until we get this right."
Source: Cobblers Mad