Everton boss Marco Silva turned on the match officials after their 3-2 defeat at Newcastle.
Silva's men looked to be coasting after Dominic Calvert-Lewin and Richarlison had given them a 2-0 lead either side of Matt Ritchie's missed spot-kick, but Salomon Rondon's strike set up a grandstand finish in which Perez struck twice inside three minutes to help the Magpies claim a fifth successive home win.
"The third goal is a big mistake from the assistant, there is nothing more to say," Silva said.
"It is clearly offside. It is not just one or two players in an offside position, it is five players in an offside position. It is a clear offside.
"The 2-2 in that moment was a big frustration for us so you can imagine the frustration of them scoring a third goal in a clear offside position.
"Ten minutes earlier the same assistant had not seen another offside when they had a chance.
"He is always seeing different things than what is normal."