Jose Mourinho was frustrated that no VAR system was used to rule out Casemiro's opening goal in Manchester United's 2-1 UEFA Super Cup loss to Real Madrid.
The Brazilian broke the deadlock in the 24th minute in Skopje, steering Dani Carvajal's long pass into the bottom corner of David de Gea's net, despite replays showing he had strayed fractionally offside.
The officials allowed the goal to stand and Isco secured the victory early in the second half, although Romelu Lukaku's strike on his competitive debut ensured something of a nervy finish.
Mourinho believes the match was largely a balanced affair and that United would have forced extra time had a video referral system been in use to check the Casemiro offside decision.
"I think we did well, I think we lost to one goal which shows the result was really short and one of their goals was an offside.