Roberto Mancini believes his Manchester City side proved in defeat that they are serious Barclays Premier League title contenders on Sunday.
City were punished for the early sending-off of Dedryck Boyata as rivals Arsenal ran out 3-0 winners at Eastlands.
The result saw City drop two places to fourth in the table as both the Gunners and Manchester United overtook them on goal difference, but Mancini said: "It is important we had the mentality during the game that we always tried to play. I am very proud of my players because we showed we are one of the best teams in the Barclays Premier League."
He added: "They played like a strong team, they played well. We lost but the way (ahead) is long.
"It was a bad result because we lost, but after the sending-off everything changes.
"Clearly it would have been better if we had won the game but if you play with 10 men against Arsenal it is difficult."
The game's defining moment came in the fifth minute as Boyata, as the last man, was shown the red card for bringing down Marouane Chamakh.
Arsenal capitalised to go ahead through Samir Nasri and it needed a brilliant Joe Hart penalty save from Cesc Fabregas, after Vincent Kompany needlessly felled the Gunners star, to keep City in contention.
Alex Song put the result beyond doubt when he pounced inside the box after 66 minutes and substitute Nicklas Bendtner added a third with a brilliant finish late on.
Mancini played down fears that talisman Carlos Tevez, who was substituted early in the second half, had suffered a serious injury, saying: "He took a knock on his muscle in the first half in a tackle but it is not a problem."