Arsenal claimed their first away in four league games to narrow the gap on leaders Liverpool to two points.
Gabriel Jesus squeezed the ball past Forest keeper Matt Turner to break the dealock in the 65th minute.
Bukayo Saka doubled Arsenal's lead seven minutes later with a clinical finish.
More to follow
Gabriel Jesus squeezed the ball past Forest keeper Matt Turner in the 65th minute
Bukayo Saka went closest to breaking the deadlock in the first-half on Tuesday night
Arsenal winger Gabriel Martinelli takes on Nottingham Forest defender Neco Williams
Arsenal forward Emile Smith Rowe has a shot on goal in the first-half at the City Ground