The Belgian defender is sure that his side can progress to the fourth round of the FA Cup in their third-round replay after taking positives from the defeat to Manchester City
The Gunners lost 2-0 at home to Roberto Mancini’s men on Sunday after Laurent Koscielny's dismissal left them with 10 men for 80 minutes in an uphill task with goals from James Milner and Edin Dzeko sealing the result before half-time.
Vermaelen and his depleted side managed to prevent any further goals and even managed to carve out a couple of chances for themselves in the second half, and though the club captain admits it was disappointing, he says that he is confident the team will respond well.
"There are a lot of big, big fixtures coming up against good teams - big games," he told the club's official website.
"This [Sunday's game] was the first one, we wanted to have a good start and that is why it is more disappointing we could not get a good result.
"But against Swansea, I am confident the group will respond on this defeat, and I'm confident we can get a result on Wednesday."
Vermaelen says he was pleased with the organisation shown from his side after they went down to 10 men, and also praised the supporters for staying behind their team in the demoralising loss.
"You know if you have 10 men you want to keep the organisation and stay in the game as long as possible," he added.
"You know it is quite hard if you play against Man City but you want to do that.
"They scored quite quickly, the first goal and the second goal, that was really disappointing. You go into half-time and then we said 'come on, we have to go for it, we’re playing at home'.
"Yes [the crowd stuck with us], that's really important and I'm pleased with that.
"That can give us a massive boost that they're behind us, and they did that through the whole game. It was difficult for us because we had 10 men and for them as well but they supported us through the whole game."