Goals from Rico Lewis and Josko Gvardiol secured the victory but the City boss believes his side could have been more clever in the final third.
While City largely dominated, Forest did hit the woodwork three times but Guardiola felt his side played well.
MATCH REPORT | FOREST 0-2 CITY
“Scoring an early goal helped us, then we continued to play with tempo but we were not clever in the final third and had three or four chances to shoot when we did not,” he said in his postmatch press conference.
“They had chances of course and we were lucky with the post we cannot deny that but in general, we played really good.
“If they win their game in hand they are in front of us in the Premier League so we know which team we are facing.
“Team with most clean sheets in the Premier League and we had so many chances. Really pleased to be in the final again.”
Watch the full press conference in the video above…