Derby were reduced to 10 men seven minutes later when Krystian Bielik, who spent last season on loan at Charlton, lunged in on Conor Gallagher and was shown a red card.

The visitors made little impression despite that numerical advantage and Derby created chances before Max Bird's cross in the 77th minute found Knight unmarked to side-foot his second.

A Curtis Davies trip on Gallagher six minutes later gave Charlton a penalty, which Lyle Taylor coolly converted, and it needed a great save by Ben Hamer to deny Ben Dempsey a late equaliser.

It was Derby's first victory since November 23 and now Cocu can call on Rooney for the first game of 2020 when he has Bielik and Tom Lawrence suspended.

He said: "If a player with the qualities, career and the experience of Rooney (is available) you have to be very happy and glad he is here, so I don't need a suspension to consider him in the first XI to be honest.

"He's fit, he can start but he will need a few games. Expectation will be high when he starts playing but we have to give him a few games to build up his minutes and get in the team.

"So maybe not perfect from the start but it's important he will get in the team as soon as possible so we get a certain shape in our team."

On the victory, Cocu said: "I'm extremely proud of how we performed in tactical discipline, how we defended and also how we played football with 10 against 11."

Charlton manager Lee Bowyer was less pleased, saying: "I'm disappointed. They had Krystian [Bielik] sent off early and in my eyes we should go on and win the game. We didn't for a number of reasons

"In possession we were poor. We didn't create anything at all. Second half until the penalty we didn't really have a shot.

"Our final ball was poor all night long. Defensively again we conceded another two goals and Derby deserved to win. We weren't good enough and got exactly what we deserved and that was nothing."