Vermaelen said that the Gunners were unlucky not to beat the Black Cats on the opening day of the season, when they were held 0-0 at the Emirates Stadium.
"Sunderland away is always a tough game," the 27-year-old told Arsenal Player. "I think we did well in the first game of the season at home against Sunderland.
"We couldn't score but we were the better team and had the better chances.
"I think Sunderland has a little bit more technical quality than Stoke. Stoke was always a difficult game."
Arsene Wenger's men are currently sixth in the Premier League.