City head into the second leg on 23 January with a 2-1 advantage over their Championship rivals.
Pep Guardiola's side will be the firm favourites but Bristol did play creditably during the first leg and led the game at half-time after Reid converted a penalty in the 44th minute.
The game also looked to be headed towards a 1-1 draw before Sergio Aguero scored during second-half stoppage time.
Reid said: "I think with the crowd behind us it will be a different atmosphere. It's a closed-in stadium and the fans are right on top. The fans will be buzzing, right behind us.
"We'll still play with that energy and desire and who knows how it will go?"