"We concede a goal, that's the main problem, it's too easy to concede, just a simple cross and a runner.

"But the positive was, we didn't lose our head, we kept playing, we improved even.

"I'm very positive about the second half, we scored an excellent goal and I think that was also the time for us to score the second one.

"We had a few good opportunities and then it was just a little bit unlucky that Kamil (Jozwiak) went off injured, the sub was not allowed, and we conceded a stupid goal that we defended very poorly.

"I'm shouting from the bench, 'Second post'. We had three defenders against one, that just cannot happen.

"It's the second game, but the pressure's on now as we don't have any points."

Berry's first goal of the season put Luton in front as he prodded home Elliot Lee's cross after 34 minutes.

Derby levelled seven minutes after the break when former Town striker Marriott scored after being teed up by new signing Jozwiak.

But Clark won it with three minutes to go, nodding home Rhys Norrington-Davies' pin-point cross.

Town boss Nathan Jones said: "I'm really pleased overall with the win, first half we were excellent and I thought that was as good as we've played.

"We were front-footed, pressed well, moved the ball and looked a real, real threat.

"I thought Harry (Cornick) was outstanding and, but for something different happening, we could have been further ahead.

"Second half I thought we took our foot off the gas, took a backward step, which I don't want us to do as you can't do that at Championship level.

"We allowed Derby on to us – fair play to them, they've changed shape, tweaked certain things, with (Wayne) Rooney dropping deep and he can cause problems if you don't get to him.

"That's the learning curve for us, but then we performed really well and, to not give up and not just be content with the 1-1, we made positive changes and a great goal to finish.

"We tweaked the shape twice and it proved fantastic in the end."