The Rams had lost five on the bounce before Saturday's win at Preston and they continued their resurgence with a hard-fought point.
"A clean sheet was a huge positive for us, I can't remember the last time we had one at home," said Clough.
"We have to put it in perspective. Having lost five on the spin it demoralises you and we have to start building again somewhere and that was the first step.
"There's no light switch to flick on and off. We are not going to go back to playing brilliant football again after losing five on the spin so we are more interested in the other side of it. It might not look very good on paper when you draw 0-0 at home but we think it's a very good point on the back of Saturday.
"I thought the back four were very, very good dealing with Millwall's threats, especially the two centre-halves. Our defending compared to five or six days ago at the City Ground was much, much improved."
Source: PA
