The Gunners drew 2-2 with CSKA Moscow on Thursday to progress 6-3 on aggregate, but their manager was worried when they were 2-0 down
Arsene Wenger admitted Arsenal were "on the ropes" against CSKA Moscow before a late salvo secured a 2-2 draw in Thursday's second leg and a 6-3 aggregate win in the Europa League quarter-final.
The Gunners took a 4-1 first-leg lead to Russia but found themselves 2-0 down and on the back foot early in the second half, with Fedor Chalov and Kirill Nababkin taking CSKA to within one goal of going through.
Wenger had switched to a five-man defence at the break but his side were consistently under pressure, until Danny Welbeck struck a fine goal 15 minutes from time to kill the home side's momentum.