Forest failed to return to winning ways in the Championship, as they played out a 3-3 draw with Blackburn away from home at Ewood Park.
“We had some really good chances, we played well and I thought that our build-up play was good in the final third,” the 27-year-old told BBC Radio Nottingham.
“Maybe we had to be a little bit more ruthless and take that last opportunity, and we could have come out on top.”
It is interesting that Mancienne mentions about Forest not being ruthless enough when they scored as many as three goals.
Stats, though, suggest that the former Chelsea defender is right in his assessment. Over the course of the 90 minutes at Ewood Park, Dougie Freedman’s side took 21 shots, but only nine of them were target.
The Nottingham-based outfit created 16 chances, but scored three times - that’s 13 chances gone to waste.
Perhaps Forest needed to have been defensively better as well. Conceding thee goals even away from home suggests that something is not right at the back, and this needs to be addressed.
Mancienne, though, insists that the Forest players were professional against Blackburn and will remain so until the end of the season, despite the fact that they have nothing to play for.
When asked if the players were relaxed due to having lost the chance of making the Championship playoffs, the 27-year-old said: “The teams were probably a little bit more relaxed than they would have been had they been fighting for promotion or something like that.
"I don’t think any teams are going to relax now. I think that teams are going to prepare for next season, and make sure that things are right and do things professionally."
Forest are currently 11th in the Championship table with 59 points from 44 matches and can still finish in the top 10.