The Reds lost the first-leg of the Champions League round 16 tie 1-0 in Madrid last night.
Reserve keeper Adrian told El Partidazo de COPE: "I think there were a couple of plays that obviously, the Wanda pressures, the fans pressure and I think the referee got carried away.
"Maybe with the goal he could take a throw-in, a couple of little things, but in broad strokes he didn't have too many mistakes either, I think."
Adrian also warned Atletico's players ahead of the second-leg at Anfield.
He added: "They should ask Barça. In Anfield nothing is lost, and I believe that the fans are already preparing for the game.
"Obviously it is going to be a game that has to be won, to make a quick goal and well hopefully they don't have that much luck in that defensive aspect."