Guimaraes put the Magpies back in front on 66 minutes and that proved to be the winner to record a fourth straight away win.
Heading into the game, the Magpies had won their three away matches and started well at the City Ground, taking the lead in the 10th minute when a short corner routine involving Miguel Almiron and Kieran Trippier saw Bruno Guimaraes volley home at the back post.
But like the Boxing Day meeting at St James' Park, the Magpies struggled to deal with balls in behind as Anthony Elanga equalised in the 21st minute after getting in between Sven Botman and Dan Burn before poking the ball under Martin Dubravka, who came charging off his line.
Forest were beginning to ask questions of the Newcastle defence but the visitors re-took the lead in the 43rd minute when Fabian Schar netted from a Trippier's free-kick that was headed across goal by Sven Botman.
That had looked to secure a half-time advantage but the hosts hit back again in the sixth minute of stoppage time after Callum Hudson-Odoi's shot deflected in off Lewis Miley.
Newcastle again went ahead of Guimaraes found the bottom right corner and this time they managed to hold on.
Our writer Jordan Cronin was at the City Ground and here's his Newcastle United player ratings: