Sanogo and Sanchez deliver as Arsenal book a slot in last 16
Arsenal put their recent troubles behind them to beat Borussia Dortmund 2-0 at the Emirates Stadium and qualify for the knockout stages of the Champions League with a match to spare.
The Gunners have endured their worst start to a domestic campaign for 30 years, and are eighth in the Premier League following Saturday's 2-1 home defeat by Manchester United.
However, Arsene Wenger's men produced the perfect response as Yaya Sanogo scored inside two minutes, with Alexis Sanchez clipping home a sublime effort at the start of the second half to inflict a first European defeat on the Group D leaders - who could still be caught for top spot should results go the Gunners' way on matchday six.
With Danny Welbeck out injured and fit-again Olivier Giroud not registered for the Champions League squad, Wenger had opted for Sanogo ahead of German international Lukas Podolski, who again had to make do with a place on the substitutes' bench.
Wenger's faith was rewarded as Sanogo took just 73 seconds to fire the Gunners ahead, when he stabbed his shot under goalkeeper Roman Weidenfeller. At the start of the second half, Alex Oxlade-Chamberlain was then unfortunate to see his sublime 25-yard volley drop back off the crossbar.
Weidenfeller was, though, beaten again when Sanchez curled in a brilliant second goal on 57 minutes, cutting inside from the left.
Sanogo's injury jinx struck again when he hobbled off with a hamstring problem, replaced for the final 12 minutes by Podolski, who got a rousing reception from both sets of fans.
Arsenal looked much more solid at the back as Dortmund never looked like mounting a comeback and Emiliano Martinez preserved a clean sheet when he saved with his feet at point-blank range from substitute Ramos in stoppage time.