Arsenal trail 1-0 at the break in their Champions League opener against Borussia Dortmund as Ciro Immobile put his side ahead on the stroke of half time.

The home side had a fast start to the game as they put the Gunners on the back foot from the first whistle. Henrikh Mkhitaryan thought he had a good case for a penalty when he was brought down in the area by Mikel Arteta, but was booked for simulation.

Dortmund were dominating the early stages and Sokratis Papastathopoulos should have handed his side the lead when a loose ball fell to his feet in the box, but he poked his effort wide of the target.

Wojciech Szczesny was forced into action for the first time in the 26th minute when the German side made an incisive break down the left. Kevin Grosskreutz crossed into the middle for Pierre-Emerick Aubameyang, but he hit his shot straight at the Gunners stopper.

Dortmund continued their assault on the Arsenal goal and Immobile's cross from the left wasn't gathered by Szczesny. The loose ball fell to Mkhitaryan six yards from the net but Jack Wilshere did enough to put the midfielder off as he blasted his shot over the bar.

Arsenal should have gone ahead when Aaron Ramsey managed to thread a pass through to Danny Welbeck on the edge of the box, but the England international scuffed his effort, which failed to threaten Roman Weidenfeller's goal.

The home side took the lead on the stroke of half time when Immobile received the ball down the right and raided into the box before firing an effort low into the bottom corner past Szczesny.