Derby were good value for their lead and the only concern for Cocu at half-time was the failure to score more goals.

Another good chance fell to Waghorn in the 54th minute when Krystian Bielik's pass sent him in on the right but his shot lacked power and Preston finally came into the game in the latter stages.

But although they had plenty of possession, the closest they came to an equaliser was a Tom Barkhuizen shot which glanced off the crossbar in the 77th minute.

Derby have now won five consecutive home games and Cocu was delighted with the way his players carried out his instructions.

"I think it was one of the best 45 minutes I have seen from the team," he said. "It was a great combination of tactical execution of the game plan and doing what we wanted to do.

"It also showed everybody that we enjoy playing together as a team.

"It's what you want to see and we could have made it a bit more easier for us and scored an extra goal, but the team recognises this more and more.

"You don't force it and go forward with everybody but just try to keep your organisation and if you don't score a second one you make sure you have a clean sheet, so this is a positive development because it would have been a shame if we had drawn after playing 60 minutes of great football."

Cocu paid tribute to Craig Forsyth, who slotted into the centre of defence for his first game in a year following a serious knee injury.

"It was a great performance from Craig after such a long time, what a game he played. His height, his vision, his passing and his experience makes it the perfect position for him," Cocu added.

Preston manager Alex Neil admitted his team had been second best in the first half.

"I thought first half we lost too many headers, too many battles all over the pitch and Derby were faster, sharper and better than us," said the Scot.

"We needed to make the second half a more open game and try and force the issue but unfortunately we couldn't get that goal.

"Like I said to them at half-time, it's quite easy for me to come in and start shouting and bawling and tell everybody how poor they've been but nothing is won at the moment and we are going to lose games along the way.

"What we've got to do is take that disappointment from today and try and make amends for the next one.

"The players understand and are frustrated for themselves but at the end of the day, we win and lose as a team.

"Sometimes I'll get it wrong, sometimes they won't perform and that's part and parcel of it."