Real also got help from the Video Assistant Referee (VAR), which made its first significant intervention in Europe's elite club competition with the era sure of an Ajax goal in the first half here on Wednesday, Efe news reported.
Real Madrid struggled to play out from the back and the handful of opportunities they got on the counter came to nothing. Ajax goalkeeper Andre Onana, who has been struggling in the domestic league, was never seriously troubled in the first half.
Courtois likewise had to be sharp to smother a shot by Hakim Ziyech just seconds before the Belgian international conceded off a corner kick.
Ajax players and supporters went wild, but the celebration ended abruptly when referee Damir Skomina disallowed the goal after an extended look at the replay on the sideline VAR monitor.
He ruled that a slightly offside Tadic had obstructed Courtois.
Unable to maintain their frenetic first-half pace, Ajax largely ceded possession to the visitors and the seemingly inevitable goal came at the hour mark.
Vinicius sliced through the defense and charged across the area before leaving the ball for an onrushing Benzema to put the visitors up 1-0.
The three-time defending champions tried to put the match to bed, but Ziyech got equalizer in the 75th minute and Ajax looked poised to secure the draw until Marco Asensio, who came on for Benzema, scored in the 87th minute with an assist from Carvajal.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)