Arsene Wenger lamented the wastefulness of his Arsenal side as they failed to make their total dominance count in Thursday night's 1-1 draw with Atletico Madrid at The Emirates.
The visitors were reduced to ten men when defender Sime Vrsaljko was shown a second yellow within the first ten minutes.
It was one-way traffic thereafter, with the Gunners missing a host of excellent opportunities before Alexandre Lacazette headed them in front on the hour mark.
But they could not find the all-important second goal, even with Atletico hemmed in, and Antoine Griezmann brutally punished them with a scrappy strike following a rare foray into the Arsenal half.
Whilst Wenger claims Danny Welbeck was fouled in the build-up to the goal, he admits his side's failure to take their multiple chances was costly.
"I feel we produced the performance we wanted to produce but the result is not in the line with the performance, and it was against a team who defends well, who don’t give too many chances away," he told the press.
"Once we were 1-0 up, the task was for clear us: not to be caught on the long ball, because they could not combine enough to come out and create the chance, the only chance they could have was with a long ball.
"We were a bit unlucky with the goal because it was a foul on Welbeck, but we can only look at ourselves after tonight’s result. 1-0 is a perfect result at home, and it was just down to us after [we scored] not to make a mistake.
"We have seen [tonight] that we had [more than] 20 shots on goal, we’ve seen that against Man United we had 33 shots on goal. It’s a story we’ve seen before."
Almighty task awaits in Madrid
The away goal means a goalless draw at the Wanda Metropolitano next week will be enough for Atletico to progress.
And, with Diego Simeone's side having shipped just four league goals at home all season, the odds are stacked against Arsenal.
Wenger, though, is confident his team can spring a surprise as he looks to finish his tenure with silverware.
"It's a special game," he pointed out. "For us the task is clear. Of course, you come out of tonight with a bitter taste, because we had the chances to be in the final tonight. We were not clinical enough, and we gave a goal away that puts you in a very difficult position.
"The only advantage of that result is that we know exactly what we have to do over there. We have nothing to lose. We have to go there and win the game."
Wenger refuses to point finger at Koscielny
After a fairly solid display, the Arsenal defence slipped up once more, with Laurent Koscielny making a hash of his attempt to clear the ball as Griezmann raced through on goal.
But Wenger shied away from criticising his experienced compatriot, emphasising instead the importance of motivating his side for the second leg.
"It’s not about blaming individuals, the whole team is very disappointed and down, so for us to have to qualify we have to get the disappointment out of the way and rebuild the desire and the confidence," he said.