It looks like a tough task for Arsenal in the Champions League tonight.
The Group F leaders take on last season's finalists Borussia Dortmund in Germany.
Dortmund triumphed 2-1 when the teams clashed in London last month.
Striker Olivier Giroud has missed only one of the 17 games played by Arsenal this season.
Chelsea can move a huge step closer to the knockout stage.
They're at home to Schalke who they beat 3-nil away in Germany a fortnight ago.
Chelsea defender Gary Cahill was impressed with their opponents despite that convincing win but he expects another victory this evening.
