The match ended with Cardiff City winning 2 to 1.
The home team earned their third league win of the season as they beat the Forest by a score of 2-1.
Jordan Hugill scored on his debut with a composed finish, as he scored in the first six minutes.
After Joe Ralls hit the woodwork with a long-range effort, substitute Isaak Davies tapped home the second goal.
Keinan Davies headed home the goal in the last moments of the game.
The visitors were never at their best in the match and will feel like they were deserving of the win.
Forest missed out on the chance to move into the play-offs for the first time this season, while Cardiff moved six points clear of the danger zone.
With four loan signings and two recalled to the club, the January transfer business reflected that the club is still in danger of being demoted.
All six of Steve Morison's squad additions started against Forest in a side showing five changes from the team that was beaten at Bristol City.
The future of Kieffer Moore will be raised further by the signing of Hugill.
Max Lowe was back in the starting XI for the game against Barnsley, replacing Keinan Davies.
The visitors have collected more points under Cooper than any other team in the league, and they have lost four of their 22 games in charge.
The Bluebirds came into this contest with the worst home record in the Championship, having only earned seven points at the City Stadium.
It took the Bluebirds just six minutes to find the net in this one, after they had lost nine of their last 10 at home and failed to score in seven of them.
Hugill was able to score after a long pass sent him clear, as Forest were careless in allowing the goal, as they both lost possession and were caught out of position.
It was a difficult debut for Doughty against Forest, but he did well.
Ralls fired over before the break, and Hugill had a shot on the turn saved by Samba.
Forest were nowhere near hitting the heights they have shown this season and their careless display was underscored by the fact that the backpass almost caught out Samba.
Johnson was able to watch the ball flash across goal when Forest did not create a clear chance until the 54th minute.
That moment was crucial as the 25-yard effort by Ralls hit the post and bounced kindly for Davies to finish from close-range.
Davies nodded home from a corner deep into the last minute after Forest pushed to get back into things.
In their last 26 league games, Cardiff have failed to keep a clean sheet, but they still celebrated as they held on to three points.
Steve Morison is the boss of Cardiff City.
That was a complete performance from start to finish.
The players carried out the game plan. They did everything I asked of them.
The players we have brought in helped us.
We have been overly reliant on academy players this season and now we have the help in the building.
The younger players can grow at the right pace and not have as much pressure on them.
Steve Cooper is the boss of the Forest.
We gave away two poor goals and it was a poor day.
We only have ourselves to blame for the loss because we weren't creative enough to threaten the goal.
We were prepared for the situation, but we let ourselves down, I am annoyed with our role in the game.
In the final third, we have been quite clinical and that was what was frustrating today, our decision making and our technique wasn't at the level.
Formation 5-3-2.
17Drameh38Ng4Morrison2McGuinness18DoughtyFormation 4-2-3-1.
2Spence27S Cook26McKenna15Lowe20Johnson37Garner11ZinckernagelThe match ended with Cardiff City winning 2 to 1.
The second half ended with Cardiff City winning.
Goal! The teams wereCardiff City andNottingham Forest. Keinan Davis headed from the right side of the six yard box to the bottom right corner. The cross was following a corner.
There is a corner in the forest. They were Conceded byCody Drameh.
The attempt was saved. The left footed shot from the centre of the box is saved in the bottom left corner. Tommy Doyle assisted with a cross.
Keinan Davis ofNottingham Forest was the culprit.
Drameh won the free kick on the right wing.
Corner in the city. Conceded by Max Lowe.
Ryan Yates won a free kick in the defensive half.
James Collins is the foul artist.
Lewis Grabban went off injured.
An attempt was missed. Xande Silva's shot from the centre of the box is wide to the right. Keinan Davis assisted.
Ryan Yates won a free kick in the defensive half.
James Collins is the foul artist.
The yellow card is shown to Ryan Wintle.
Ryan Yates ofNottingham Forest had a foul.
The attacking half has a free kick.
There is a substitution for Cardiff City. Will Vaulks replaces Joe Ralls.
Ryan Yates won a free kick in the defensive half.
The foul was committed by Isaak Davies.