Arsene Wenger's men also failed to find the net at home to Sunderland during the opening Premier League weekend.
However, Vermaelen prefers to remain positive.
He told the club's official website: "There is always pressure to win at Arsenal because we want to win every game.
"But you have to look at the positives as well; our shape is really good and we haven't conceded any goals in two games.
"That is not easy, especially at a place like Stoke, so we have to keep working and in the end the results will come. I think the team will get stronger and stronger every game now."
New signings Santi Cazorla, Olivier Giroud and Lukas Podolski have all featured in Arsenal's opening two games, and Vermaelen believes they will also continue to improve as the season goes on.
He continued: "The new signings are working hard but coming to England is not easy and you have to adapt. That is especially true when your second game is away against Stoke.
"I am really pleased with them, they are three good signings and they are working hard to get fitter and stronger."
Arsenal's next game is away to Liverpool on Sunday lunchtime.