#2 Inability to make use of the man advantage
Seeking whatever sort of positive result, Arsenal were handed the ultimate advantage very early in the game as Atletico Madrid's right-back, Šime Vrsaljko, was first shown yellow when he brought Jack Wilshere down in the 2nd minute, before subsequently being shown red for catching Alexandre Lacazette in the 10th minute.
Now, to have a side like Atletico reduced to 10 men that early was undeniably a blessing for Arsenal, who seemed to do everything they could barring their success in the final third.
With 76% possession, 28 shots, 762 passes, 11 corners, and a passing accuracy of 89.1%, Arsenal may have outplayed Atletico Madrid (23.9% possession, 6 shots, 245 passes, 0 corners and a passing accuracy of 68.6%) but statistics don't paint the entire picture.
At the end of the day, the Gunners will rue the fact that they could only muster the one goal while also allowing as many. The second leg of the semi-final is scheduled to be played at the Wanda Metropolitano on the 2nd of May, and the Arsenal faithful will pray for any kind of miracle.