Expectations were high ahead of the duel at Stamford Bridge on Wednesday between the traditional London rivals but the contest offered little in the way of entertainment or excitement, reports Efe.
The real protagonist of the match was the Video Assistant Referee (VAR) system, recently introduced into English football.
Head official Martin Atkison consulted VAR three times in the first half.
But while the VAR ruled no penalty after the Gunners' Ainsley Maitland-Niles leaped to avoid a late challenge by Victor Moses, television replays appeared to show contact by the Blues player.
David Ospina, starting in goal for Arsenal in lieu of Petr Cech, made a pair of good stops in the first 45 minutes and made another vital save in the second half against Alvaro Morata.
The two sides will play the second leg on January 24 at the Emirates.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
