Arsenal's 2-0 victory over Bayern Munich may have been an excellent result but in the grand scheme of things it may only be a temporary lifeline if they do not get a result at the Allianz Arena this evening.
Defeats to Dinamo Zagreb and Olympiacos in their opening two group games still leave Arsène Wenger's side on the brink of elimination.
As much as a point in Bavaria would be a relief to Gunners fans as it would leave qualification to the second round in their own hands. Defeat, and it's in the hands of Bayern Munich and Olympiacos.
The worst case scenario for Arsenal this evening is defeat matched by an Olympiacos win at home to Dinamo Zagreb. The Greek side won in Croatia a fortnight ago and are heavy favourites with the bookmakers to pick up three points this evening.
Those results would make it impossible for Arsenal to finish above Bayern Munich and would mean Olympiacos only need one point from their final two matches to finish above Arsenal. Even then, the Gunners also need to win by two goals in the Greek capital, or win with a score of 3-2 or higher, to win the head-to-head.
If Arsenal were to draw at Bayern Munich this evening and Olympaicos still beat Zagreb, the rest of the group remains in Wenger's hands. The Gunners could then get to 10 points, and would then need to win the head-to-head over Olympiacos to go through. Whether the result between Bayern Munich and Olympiacos is a draw or not, the Premier League side would then have the superior head-to-head if either side finish on 10 points.
Victory for Arsenal in Germany tonight and they would be in with a great chance of winning the group.
It's by no means certain that Arsenal will win in Greece and beat Dinamo Zagreb at home given the results of their first meetings, but I am confident they would pull these victories off if they can get another result versus Pep Guardiola's side first.