Disappointed Paul Cox says his players must learn to win their individual battles if Mansfield Town are to be successful in League Two.
Cox was left fuming at the non-existent marking which allowed Kaid Mohamed to head past Sascha Studer in the 26th minute and seal a 1-0 win for Northampton.
“I am disappointed to have lost a game from a restart,” Cox said. “That is something that we work on in training and something that is normally our strength.
“It was that goal that undid us and something that we need to learn from. We did not defend the cross and allowed the lad to have a free header.
“I want the players to go out and play, but the reality is we have to win our individual battles and we did not do that for the goal.
“I thought up to that point we were playing some good stuff and on top in the game.
“Pre-season is very easy when teams are giving you time and space and are allowing you to play.
“We were a bit too erratic towards the end and need to make better choices as a team in the final third.
“It was in the final third where we lost this game today. We have to accept the score, it has brought the playing staff down to earth.”
Stags had come back strongly after falling behind and nearly drew level through a Ryan Tafazolli header and a thunderbolt from Rob Taylor in first half stoppage time.
And, with Northampton guilty of some very wasteful finishing, Mansfield also enjoyed a late flurry of half-chances through substitutes Liam Hearn and Sam Clucas in the dying minutes of the game.
But it was too little too late as Stags were left to reflect on a disappointing start to their League Two campaign
Stags were also dealt a blow after striker Ollie Palmer limped off after 55 minutes with ankle ligament damage, which is likely to keep him out for between two and three weeks.
That means Cox will have just Hearn and Fisher to select from as Matt Rhead continues to serve his suspension.
But, despite his disappointment, Cox said there were positives to be taken out of the game.
“I will not throw myself off the rooftop because we have lost one game,” said Cox.
“What we need to do now is improve on the little things that got the better of us.
“It is the first game of the season and we have got a lot of news players, I don’t expect us to be the finished article at this stage.
“There are positives to have come out of the game. We looked a bit leggy in the final third, but that will be sorted with more game time for Liam Hearn and getting Matt Rhead back.
“I thought Hearn and Clucas had an effect when they came on. If we can improve in both boxes then we can become a good team.”
Stags will look to get their first three points of the season when they play host to Oxford United on Saturday.