Vermaelen was at the heart of an Arsenal defence that lost their first game of the season against Chelsea last weekend.
The Belgian international told Arsenal's official matchday programme that he is pleased another game has come around so quickly so that his team do not have to dwell on the loss.
He said: "We have to bounce back against Olympiakos and I am confident that we will.
"It's always nice to have another game shortly after a defeat, and particularly at home.
"On top of that, it's a different competition and different opposition, and a new occasion all round, so it should be an interesting night."
Arsenal face the Greek champions in the group stages for the third time in four seasons, with the home team winning each of the last six meetings.