A tight clash was decided by Callum Hudson-Odoi’s late winner despite City having greater possession and more shots on the day.
Nico and Mateo Kovacic came closest for City either side of Hudson-Odoi’s winner, with the former striking the post and the latter’s volley whistling narrowly wide.
Ederson had also been forced into a magnificent save in the second half, clawing a Hudson-Odoi shot on to the post after a quick Forest break.
The result means Forest strengthen their grip on third in the Premier League table, with City in fourth ahead of the chasing pack playing later in the weekend.
After the match, Guardiola spoke to the assembled press to reflect on the performance.
Watch the full press conference at the top of the page...