Arsenal's manager Arsene Wenger bemoaned his side's 'naivety' in their 2-1 loss at home to Borussia Dortmund.
The Frenchman's side fell behind in the early stages with Henrikh Mkhitaryan capitalising on Aaron Ramsey's dwelling on the ball.
Marco Reus dispossessed the Welshman and the ball fell kindly to Mkhitaryan to slot home.
Arsenal did well to get back in contention with his side battling to get into the game. Just on the stroke of halftime, Bacary Sagna crossed a delightful ball between Weidenfeller, Subotic and Olivier Giroud, which lead to mix up between the Dortmund players which lead to the ball landing at Giroud's feet to smash home.
With the score at 1-1, Arsenal smelt blood in the second half.
With Santi Cazorla coming on for Jack Wilshere, Arsenal were a lot more comfortable in possession.
Although they had most of the possession in the second half, they failed to make many opportunities.
This lead to frustration and them pushing even more players up to find the winner. This lead to Dortmund's winner as they broke rapidly with Großkreutz crossing to find Lewandowski at the far post, unmarked, to slide home leaving Szczesny with no chance.
It's quite a hard match to judge where Arsenal are at. Many pundits and fans alike were hoping to see where the side is with such a big game against Dortmund. But with Dortmund playing very reserved and waiting to counter, it's impossible to measure how Arsenal will fare against the big clubs.
Although Dortmund weren't at their best, their relentless pressure off the ball paid dividends. Such as for the first goal, pushing Ramsey into a mistake, they kept the pressure on all night. It made Arsenal feel very uncomfortable and they labored to make any real chances.
Wenger believed his side lost due to being naive and looking to win the game when they should have been less gung-ho.
He said: "We put ourselves on the back foot with the first goal and were naive for the second."
With Wojciech Szczesny not having to make many saves during the match, it will leave Wenger unhappy that they slipped to a defeat against Dortmund.
Wenger said: "Look at how many saves our goalkeeper has had to make and we have conceded two goals. We can only look at ourselves as not being mature enough in those situations. If you can't win the game, don't lose it."
With his side slipping to defeat, this leaves Napoli, Arsenal, and Dortmund on six point in the group. With everything to play for Wenger said his side's chances of reaching the next round are, "Tight and difficult - but possible."
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