Cape Town - Unai Emery heaped praise on Blackpool after overcoming the League One side 2-1 in a tight League Cup victory on Wednesday night.
Stephan Lichtsteiner broke the deadlock at the Emirates on 33 minutes before an Emile Smith Rowe goal on 50 minutes went some way to settling the tie.
But a second yellow card for Matteo Guendouzi on 56 minutes left the Gunners vulnerable as they soon conceded to Paudie O' Conner with 66 minutes on the clock.
The Blackpool goalscorer was subsequently dismissed with a red card on 84 minutes, as Arsenal claimed their place in the quarter-finals with Tottenham Hotspur.
After the match, Emery told the club's website: "For me, it's a very organised team. Tactically they do very well and it was difficult to win against them. They have players with quality. I don't know the level in League One for this team against other teams, but for us I know, and I spoke before the game with people to know the level of this team.
"I know that this team was in the Premier League eight years ago. It's a reason also that firstly I have respect and secondly because I want to win each match, like today against Blackpool. We needed our performance with a big preparation."
He added: "In the 90 minutes, a lot of things happened in the game but I think we controlled a lot of moments in the match and we were 2-0 up and the match is, for us, in a good moment.
"This red card to Matteo affected the balance more for them and their goal also, we can and we need to continue our work to the last minute with our performance and our players to win today. But I think that doing our work, we deserved this victory also."
Looking ahead to facing Spurs, Emery said: "We are here to do one thing in this title and we are going to play against the big teams. I think this is the moment also to play the first derby against Tottenham.
"For us, it's different if we play away or if we play here at home. I think it's important for us to play here with our supporters at Emirates. I think this is the moment for both clubs, a great moment, but only one can win."