Vermaelen voiced his concerns about Arsenal's collective defending after the match but he knows the squad must maintain its spirit ahead of a testing run of games in the FA Cup and Premier League.
"We are disappointed with the result, with the way we played, but I think we have to stay confident and the spirit has to be good all the time," Vermaelen told Arsenal Player.
"It's true [our form is good], of course we want to win every game, that's why a draw is [disappointing], but we didn't lose and before we won four games. In the league everything is really close, everybody can win against everybody. It's a tight race and we are confident.
"We didn't play our best game [against Southampton], we didn't create a lot of chances to score goals. Even the goal [we scored] wasn't a chance in my opinion. It wasn't a great afternoon.
"Wojciech had to make a few saves, I think our overall defending as a team can always be better. I think the space between the defence and our strikers was too big so they could have play their game if they wanted. We have to work on that, it has to be better."