Forest bounced back from midweek’s 2-1 defeat to Charlton Athletic at The Valley with a 2-1 victory over Middlesbrough at the City Ground on Saturday.
Boro took the lead in the Championship clash in the 27th minute when Grant Leadbitter's cross ended up in the net.
However, Dougie Freedman’s side launched a comeback and scored twice to pick up all three points.
Gary Gardner equalised for the Reds in the 34th minute when he shot home from distance, and Dexter Blackstock scored the winner midway through the second half on his 150th appearance for the Nottingham-based outfit.
Mancienne, a former Chelsea defender, featured for the entire 90 minutes and explained why they could beat one of the strongest teams in the Championship.
“Everyone put a shift in and worked hard for each other,” the 27-year-old told Forest’s official website. “For periods of the game Middlesbrough had a lot of the ball, but we stayed in our shape and stayed focused.”
The fact that the Middlesbrough players worked hard is proved by the stats in the following Opta Stats tables:
Forest are currently ninth in the Championship table with 53 points from 36 matches, nine points behind sixth-placed Brentford.