Dedryck Boyata saw red for City after just five minutes after he brought Marouane Chamakh down with the striker through on goal.
Samir Nasri put the Gunners ahead before Fabregas saw Joe Hart save his penalty after the Spaniard had been fouled by Vincent Kompany.
But Alex Song and Nicklas Bendtner struck in the second half to seal a 3-0 win on Sunday.
And Fabregas told Sky Sports 1: "I think we played some outstanding football and it's difficult to stop a side when they play at that tempo. It's very difficult what to know what will happen (over the rest of the season) and we have an important game on Wednesday (against Newcastle in the Carling Cup), but it's a good victory against a good team."
The Spain international did not believe the sending off changed the course of the game.
"Even if they were 15 and we were 11 we would still go and win," he added. "We always want to go forward and create chances but the way we played today, we were very difficult to stop. I think we were fantastic."
The Gunners are now five points behind leaders Chelsea, but Fabregas does not see the Blues as title favourites.
"Chelsea are looking strong but they have to play a lot of the big teams. We have to keep calm and think about the Carling Cup and then we think about West Ham next Saturday and getting back into the league."
Manchester City manager Roberto Mancini did not agree with Fabregas' assessment, believing his side would have won the game if it had been 11 versus 11 and that they had proved themselves to be one of the best teams in the Premier League.
"I think it was the worst moment to go down to 10 men but I am very proud of my players. They played well and stayed in the game until the second goal," he said.
"I think after today we must say we are one of the best teams in the Premier League. If it was 11 against 11 we would have won this game."
Mancini was also not convinced that Boyata should have seen red for his tackle on Chamakh, citing a lack of consistency among referees.
He continued: "I don't know because against Newcastle we had one penalty from a tackle by the last man and the referee gave a yellow card."