Published: 22 October 2013
By RICHARD OSLEY at the Emirates Stadium

UEFA Champions League, Group F:
Arsenal 1   (Giroud 41)
Borussia Dortmund 2   (Mkhitarayan 16, Lewandowski 82)

Arsene Wenger warned tonight (Tuesday) that Arsenal had left themselves with a "difficult" task to qualify for the second round of the UEFA Champions League after falling victim to a late sucker punch goal in a 2-1 home defeat to Borussia Dortmund.

"It will be tight," he said. "It is difficult but possible. We have three teams on six points in the group but we've played two of our three games at home already, which means we need a result away from home now."

Despite Arsenal's roaring start to the season, Wenger said his team lacked the maturity to settle for a point against their German visitors, last year's beaten finalists in Europe's elite competition.

He said: "If you look at the number of saves our keeper actually had to make today, then you see that we caused our own problems. We were not mature enough. If you cannot win the game, don't lose it."

That sentiment summed up Arsenal's downfall.

There was no need to chase the win against Borussia Dortmund, having already won their first two fixtures against Marseille and Napoli.

But there was a thirst for victory as the attacks became more cavalier as the second wore on, perhaps inspired by a slick passing move in which substitute Santi Cazorla grazed the crossbar with a flying, looping shot.

The win was there for the taking, the home fans clearly felt, but it should not have been sought at the expense of allowing the yellow swarm from Dortmund to sweep up the pitch themselves, initially from a wretched Bacary Sagna cross, and snatch victory through Robert Lewandowski's smart volley.

The striker had been earlier booked for an elbow, which on another day could have provoked a red card but replays did not seem to show malice. His finish, eight minutes from time, was sublime.

Truth was, Dortmund would've surely been happy to take a point after a rainy second half spent largely on the backfoot, but the capsizing Arsenal defence was an invitation that would have been rude to repel.

Wenger said: "Dortmund were very organised, they stopped us playing. They are the strongest side physically we have met."

It was, however, an even match-up: two classy sides, full of intelligent ball players, albeit occasionally flawed by implausible lapses in concentration.

Aaron Ramsey, brilliant again at times tonight, was caught in possession on the edge of his own box early on to gift Dortmund the led. The ball eventually fell to Henrikh Mkhitarayan who rolled it in with Wojciech Szczesny in no mans land.

The only blessing was that it woke up Arsenal from a sleepy start and by the break they had merited their equaliser, if claimed in fortuitius style.

This time Dortmund switched off as Sagna swung in what was actually another wretched centre, only for defender Neven Subotic and keeper Roman Weidenfeller to get in each other's way. Olivier Giround was suddenly all alone with the goal gaping and could not miss.

Tomas Rosicky had previously had a stinger cleared off the line.

The job of qualifying may now demand a home victory against Marseille and away draws in Naples and the return leg with Dortmund. That should be enough, but it will be more nervous that it might have been.

Attendence: 60,011

Arsenal: Szczesny, Sagna, Gibbs, Koscielny, Mertesacker, Rosicky (Gnabry 89), Arteta (c), Wilshere (Cazorla 58), Ozil, Ramsey (Bendtner 87), Giroud
Subs not used: Fabianski, Vermaelen, Monreal,  Jenkinson, Gnabry

Booked: Rosicky, Ozil
Sent off: None

Borussia Dortmund: Weidenfeller (c), Grosskreutz, Schmelzer, Subotic, Hummels, Bender, Sahin, Reus (Papasthopoulos 87), Blaszczykowski (Aubameyang 67), Mkhitaryan (Hofmann 67), Lewandowski
Subs not used: Langerak, Kirch, Schieber, Durm

Booked: Hummels, Lewandoswki, Bender
Sent off: None