Manchester City striker
City's second UEFA Champions League campaign began with a dramatic last-gasp 3-2 defeat to Real Madrid at the
Aguero, who was linked with the Spanish champion last season, watched a pulsating encounter unfold from the bench as an unused substitute and is convinced City will bounce back.
The former Atletico Madrid player tweeted after the game: "I feel comfortable and appreciated in @MCFC - it's a project I feel involved in. We want more titles and we'll get them!"
And to underline his commitment to the club after returning to a city where he is always the subject of press interest, he added: "Just to make it clear - I'm very happy to be in @MCFC. It's the best decision I could have taken."
Aguero, 24, scored 30 goals for City last season after joining the Barclays Premier League champions in a £38 million ($59 million) club record deal.
He is yet to make an impression this season having suffered a knee injury in the opening Premier League fixture against Southampton last month.
He had hoped to make his return in the Spanish capital but events prevented manager
Mancini said: "I had two players injured, (
City was beaten in a remarkable finish as Karim Benzema and
The result leaves City playing catch-up in a tough-looking Group D that also includes Borussia Dortmund - also a winner on the opening night - and Ajax.
Mancini said: "I think other teams will lose here. Now we have five games and it is important we beat Dortmund next game at home.
"We know it will be difficult playing against a top team but this year we want to go through."
City failed to get beyond the group stage in its first Champions League campaign last year.
UEFA Champions League
A last-gasp Arjen Robben goal helped Bayern Munich to a 2-1 win over Borussia Dortmund in the UEFA Champions League final at Wembley.