An impressive 2-0 victory at eventual champions Bayern Munich in March proved the catalyst to the superb winning streak, which this term has seen Fenerbahce, Fulham and Sunderland fall by the way side.
Arsene Wenger's side are hoping to add Marseille to their impressive list of conquests this evening as their Group F campaign kicks off at the Stade Velodrome.
It is a match of significant importance as sterner tests against Borussia Dortmund and Napoli await, with centre-back Mertesacker confident of collecting another important win.
"We have an exceptional team - that's the main thing," the Germany international said.
"We built up confidence from last season, especially the last 10 games when we didn't lose anything.
"You could feel it from the first day that there is something special in this team, apart from the first game [against Aston Villa], no one dropped and the performance went well after that.
"We have shown so far that we are ready to keep our confidence and keep the run going. The most important thing is to keep that mental level high and to be prepared for because it will be hard.
"They will put pressure on us so we need to be aware of that, particularly in the first 15-20 minutes."
The chances of Arsenal starting with their campaign with three points look to have been dramatically boosted by the news Mesut Ozil and Olivier Giroud are available.
Source: PA
Source: PA