Liverpool lost a two-goal lead against Atletico Madrid in controversial circumstances during their Champions League opener.
The Reds scored two early goals via Andy Robertson and Mohamed Salah but were pegged back shortly before half-time.
Marcos Llorente poked the ball into the bottom corner in added time with his third Champions League goal for Atletico at Anfield.
Replays appeared to show Antoine Griezmann standing in an offside position beforehand.
Although he didn't touch the ball, he was in the eyeline of Liverpool goalkeeper Alisson as the shot was taken.
However, the goal was allowed to stand and made the scoreline 2-1, but it drew criticism for perceived interference.
"Well you can understand why Alisson was immediately out speaking to the referee," Jim Proudfoot said