City had an early lead through Erling Haaland before Arsenal fought back through goals from Riccardo Calafiori and Gabriel Magalhaes. Arsenal then had Leandro Trossard sent off on halftime.
The Gunners sat deep in the second-half and it wasn't until on 98 minutes that substitute John Stones scrambled home a City equaliser.
Arteta said, “We know how difficult it is already against this team here, that's the reason why they haven't lost for over a year. We struggled in the first 10 to 15 minutes to control certain spaces and they scored the goal, but we reacted incredibly well.
“We showed unbelievable character and personality and then we had the game where we wanted it. The team showed again that it’s ready in any context, that it’s strong, with people cramping against 10 men. For 56 minutes to do what we've done is remarkable and it's a shame that at the end we haven't managed to win the game.
“The team has this character, this personality, and we showed it today in probably in the most difficult stadium in Europe.”
On adjusting at the break after Trossard's dismissal, Arteta also said: “We had to adapt to the context, explain the game that we have to try to play, and how we could prevent certain things, not all of them - that's going to be impossible for 56 minutes, especially mentally. We had to be ready to be so disciplined, and make a lot of defensive actions because we knew the game that was coming.
“We came here to win, that's the reality. And within the difficulty, obviously we were thrown an aspect that we didn't think about. But we got at least a draw, and we have to move on.”