Arsenal manager Mikel Arteta was not impressed with his side in the Champions League.
The Gunners found themselves 1-0 down after the end of their first leg against FC Porto.
Now they must win at home by a two-goal margin to progress to the quarter finals.
On the display, Arteta told reporters: No. Obviously I am very disappointed the way we gave the game away at the end.
Not managing that situation well enough. You get punished in the Champions League. If you cannot win it, you don't lose it. We really dominated the game but we lacked purpose, especially in the first half. You need to have much more aggression, you need to break lines, to play forward and generate much more threat on that backline.
In the second half there were much better things and we generated a lot of situations, without really creating much from it. We will learn from it. Now it is clear, it is half-time. If you want to be in the quarter-finals you have to beat your opponent and that will be the purpose and the plan, with all our supporters together."
Asked if his team was naive on the night, he added: Well it's only the last ball, so if in 94 minutes they haven't had any naivety other than that one, I think it's a bit cruel to judge it. But it's true that it has had a big impact on the result. A lot of other things they did for the first time here were very good."