Gareth Bale's superb goal in injury-time secured a hard-fought 3-2 win at West Ham on Monday night, which moved Spurs up into third place in the Barclays Premier League and four points ahead of the Gunners, who are fifth.
Sigurdsson, though, maintains his side can not take their foot off the gas even if Arsene Wenger's men get a sound beating at White Hart Lane.
"It is going to be a massive game for us," said the Iceland international, who bundled in his first Premier League goal for Spurs which sparked a late comeback at Upton Park.
"However, anything is possible in football. The league was won in the last minute on the last day, so even if we beat them it is not finished.
"First, though, we have to beat them to start thinking about that.
"It will be a great atmosphere. Hopefully we can get a win and stay above Chelsea.
"We want to get in to the Champions League, that is our aim. If we achieve that, we want to finish as high as we can."