Ordinarily a team boasting a commanding 3-0 first-leg lead would be described as having one foot already firmly planted in the last four, but Los Blancos are the undisputed kings of high-profile European comebacks and cannot be written off just yet.
Carlo Ancelotti’s holders were blown away in shocking fashion at the Emirates Stadium last week, with Declan Rice netting two spectacular free-kicks to go along with Mikel Merino’s effort before Eduardo Camavinga was then sent off in stoppage time.
It has left the record 15-time European champions with much work to do to keep their latest trophy defence alive, having kept in touch with arch-rivals Barcelona in the LaLiga title race with a nervy 1-0 win at struggling Alaves on Sunday in which Kylian Mbappe was sent off.
A low-key 1-1 draw with Brentford in the Premier League was hardly the best preparation for a trip to the Bernabeu, but the Gunners can be forgiven for having all of their attention on this game with the title race long since lost.
How to watch Real Madrid vs Arsenal
TV channel: In the UK, tonight’s match is being shown live on TNT Sports 1, with coverage beginning at 7pm BST ahead of an 8pm kick-off.
Live stream: TNT Sports subscribers can also watch the game live online via the Discovery+ app and website.
Live blog: Follow the action as it happens with Standard Sport’s live blog, featuring expert analysis from Arsenal correspondent Simon Collings at the Bernabeu.