The Premier League outfit went down by a Luis Diaz goal in the opening 14 minutes but Sergio Aguero pulled parity for the hosts six minutes later from the penalty spot.
The Portuguese side defended in their numbers and kept Manchester City at bay for the vast majority of the game until Guardiola’s men found another way through on the 65th minute mark kind courtesy of IIkay Gundogan and Ferran Torres delivered the coup de grace 17 minutes before the end of the game.
Guardiola was happy with the victory and is looking forward to City’s next Champions League game.
"The last 10-15 minutes of the first half and the start of the second we played well,” the Spanish coach told reporters.
"This is a good start for us and the next step we go to France to get the second one.
"At set pieces they were strong. By the second half we didn't concede anything set pieces or counter attacks so we controlled the game.
"Here in Champions League is an opportunity to play five substitutions and the ones that came on made incredible contribution.
“We had decided before the goal [to substitute Gundogan] but he made an incredible goal.
"Teams that set up with lots back you have to wait for your moment. We adjusted a little something at the end of the first half.
“We spoke about being patient, we had to be patient and at the right moment attack them, so we let them run."
