Aidan strung some words together in a very informative fashion about this match here, so I won't reinvent the wheel. Or plagiarize the wheel. Or whatever. The job is easy to explain; gain points. Or avoid a blowout loss, but considering that Arsene will field as strong a lineup as he possibly can, the former is hopefully the more likely outcome. A draw or a win wins the group, but even a loss by less than three goals means Arsenal will advance.
Considering that Arsene has called this one of the defining matches of their season, though, I highly doubt Arsenal will be playing for the draw; even in the hostile Stadio San Paolo, Arsenal will try to be on the front foot and try to get something from this game.
You know the rules; be cool to each other, no posting of or discussing illegal streams, and, well, that's about it really. Let's do this.