Town slipped to a 3-2 defeat against the Magpies at York Road on Tuesday night.
The Blues started slowly and found themselves two-nil down after 20 minutes. They fought back to level the score before conceding a late third.
Rowe told the DT: “Training has been excellent up to yesterday (Monday) but the players did not perform well enough in training and they took it into the game. Training has been really good since Chelsea but for some reason our eye was not on the ball yesterday in training, they did not train to the levels they can, and this is the result. We don’t start right and you are climbing a mountain. At 2-2 with 20 minutes to go you need to focus and make sure you don’t concede the third because they (Maidenhead) didn’t look like they were going to score and we have let them in from a set-play.”
The goals Chesterfield conceded were uncharacteristic and were of their own doing on what was a disappointing night in Berkshire.
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"They were shocking goals to concede,” Rowe said. The first, perhaps Scott (Loach) could do better, he got a hand to it, I need to see it again.
"The second one, I have seen it again. It was poor play from us to let them get it in there in the first place and a poor foul and Scott should not be beaten at that side, you protect that side, if it goes over or under the wall and in the corner then you take your hat off.
"The third goal, we are quite high up in the charts in terms of set-plays, we have done well in both boxes, that (the winner) was probably a reflection on the evening that we were not quite at it and when you are not at it in the National League you get punished.”
The Spireites are next in action at home to Rowe’s former club Aldershot Town on Saturday.