The Reds took the lead at Aggborough through Tom Allan's first half goal before two goals in 2 minutes from the hosts in the second half condemned Alfreton to defeat; despite a fluid, creative and hard-working performance.
McDermott told the club`s press officer Amar Sharma: "I felt we started the first half really well, we were brilliant throughout. This was a full-time team and they've been working on things morning and afternoons and we competed and matched them, more than matched them in the first half.
"We got a good goal and we could have more in the first half. Chris hasn't had to make too many saves, set pieces we looked dangerous on and they tried to move us around but we held firm and they didn't hurt us. I was very happy at half time."
A lack of concentration during the second half suddenly turned the game on its head and the boss was disappointed: "We mentioned what would be our undoing at the break and we knew it wouldn't be the fitness, it would be a lack of concentration at a set piece or we would get blocked and it's exactly what happened with the first one. We let the lad come across us and we switched off.
"The second one we switched off again, he's come in late and yes he's mis-kicked it, yes Chris Elliott should save it, it shouldn't have been a rebound but no one will save us with those mistakes. They should not get the first one in.
"We need to make sure we cut those things out, we can't afford to switch off or lose concentration especially from winning positions. It's something for us to make sure we don't do. We start cutting it out, we get points on the board."
McDermott was also proud of the Reds performance, despite defeat: "I can't have a go at the players, they were outstanding, they gave everything and that's all we can ask. We need to be realistic about what we are coming up against and they will be up there this season. And I've seen signs, especially in the first 45 minutes that we aren't too far away either.
"Yes we need to work on stuff, and yes we will work on stuff, but we aren't far off."
Alfreton welcome Curzon Ashton today and McDermott stressed the importance of a result: "We play Curzon today and we have got to win it, we don`t want to be too far away and we need to start winning our home games, we've won two already and we need to win against sides that we should be beating and that I expect us to beat. We've got some tired legs but so will Curzon Ashton, they also played Saturday, there isn't an excuse.
"We need to brush ourselves off, i'm proud of the players who put in a miles better performance then the game against Southport. I'm disappointed with the result but I felt we were outstanding especially in the first half and we are improving, it's important we take it into Monday."
On Brendon Daniels and Ricky German, McDermott added: "Brendon looked good on the ball and he looked a threat, his set-pieces were dangerous and he looked like he could get us a goal. I was happy and he needs to work some more on his fitness, but he hasn't played a lot of games but he will come good. He's not a miracle worker but he has plenty of quality and it will help us. We're a good team and once we settle I know we can show that.
"Ricky showed some good glimpses when he came on, it's always tough coming on second half. He's had two efforts which the keeper has saved and it says it all that their keeper got man of the match. He's quick, strong and the experience will only improve him".