Arsenal fans were forced to endure a heart-breaking European defeat at the hands of Borussia Dortmund on Tuesday evening.
Jurgen Klopp's men proved nightmare opposition for Arsene Wenger's side as they returned to Champions League group stage action. Ciro Immobile and Pierre-Emerick Aubameyang scored the goals on the night, condemning the Gunners to defeat.
However, a rather worrying statistic has arisen from this tie; highlighting perhaps the main reason for Arsenal's defeat: as a unit, Dortmund's players ran 11km further than their Premier League visitors.
Overrun by the German outfit's superior pace and work-rate, an Arsenal midfield chock-a-block with creative talent failed to make an impact in the final-third, while the defence wilted under the power of their opposition's attack.
The club will have to improve significantly after a woeful display in which they were outfought and outplayed for long periods at Signal Iduna. Ultimately, they were completely outclassed by Dortmund and will be grateful that the Bundesliga outfit did not score more than two goals.
They now face a tough task to top Group B, but will receive some comfort in the knowledge that rivals Galatasaray and Anderlecht drew 1-1 in Turkey. Having said this, they must improve significantly, or else they could be caught out in their remaining matches.