Borussia Dortmund 1-1 Arsenal
Arsenal's hopes of starting their Champions League campaign with an away win were dashed when substitute Ivan Perisic's superb late volley rescued a point for Borussia Dortmund.
Robin van Persie looked to have secured the points for the Gunners with a fine goal from Theo Walcott's through ball.
But Perisic dipped a sublime 20-yard shot home to salvage a draw.
And only a fine Wojciech Szczesny save from Robert Lewandowski in injury time stopped Arsenal finishing with nothing.
A defeat would have been harsh on the Gunners, especially after an improved rearguard action in the second half, but few could begrudge the German side a point from a match they dominated for long spells.
In fact, for 40 minutes in the first half Arsenal were kept almost completely on the back foot.
After Gervinho had been brilliantly denied an early shot on goal by Mats Hummels' outstretched boot, the German champions made a mockery of their fourth-seeding in this season's group-stage draw.
Mario Gotze was inventive, Lewandowski a menace, and Shinji Kagawa a constant source of energy as, time and again, the hosts played through a porous Arsenal midfield.
Kevin Grosskreutz fired over when well-placed in the box, Kagawa did similarly after being put through on goal and then Lewandowski, having rounded Szczesny, was denied by Bacary Sagna's goalline clearance.
With the Gunners far too lightweight in midfield, Mikel Arteta dropped back into a deeper-lying role. This freed Yossi Benayoun to go further forward, a move that helped forge a rare Arsenal chance on 30 minutes when the Israeli released Van Persie, only for the Dutchman's snap-shot to be tipped around the post.
Dortmund continued to control proceedings, however, and it looked only a matter of time before they would break through.
But then Arsenal scored. Sebastian Kehl's poor touch ended at Walcott's feet via Van Persie. The Englishman's return pass was a delight, allowing Van Persie to take a touch before rifling a rising drive past Roman Weidenfeller.
It was a big goal at the perfect time for the Gunners - and Wenger, seated in block 27, row 24, seat 63 of the 80,000-capacity stadium as a result of his touchline ban, will have liked what he saw after the break, too, Arsenal emerging in far better shape than they did the first.
Though Dortmund continued to boss possession and territory, they did so with far less venom than in the first half with Arsenal frustrating them by dropping a touch deeper and looking a lot more compact in midfield.
The outstanding Alex Song was at the heart of that for the visitors, and he played his part in creating a chance for Gervinho on the hour mark. The Ivorian danced past Neven Subotic and then Hummel before being denied by Weidenfeller.
With the clock ticking down and the hosts increasingly erratic in their attacking play, Arsenal looked comfortable.
It was then, though, that Dortmund finally produced a killer finish. Kieran Gibbs's half-clearance fell to substitute Perisic, who unleashed a fabulous dipping volley into the top corner.
Buoyed by their late strike and driven on by a rejuvenated and passionate home crowd, Dortmund went in search of a winner.
Lewandowski almost provided it in the dying seconds when he found himself one-on-one with Szczesny, but could not force the ball past the Polish keeper.
In the end, then, the Gunners were grateful for the final whistle - though a decent away performance overall should ensure they go into Matchday Two in a fortnight's time against Olympiakos in a confident mood.