The 3-0 thrashing of their fellow strugglers on Tuesday was only the Black Cats' THIRD league win in the last 24 games.
Victory lifted them up to 15th and Belgian keeper Mignolet said: "Relief probably summed up the feeling in the dressing room.
"We knew Reading was a massive game. There was a lot of pressure."
Mignolet also joined the chorus backing boss Martin O'Neill, who took flak for their poor run.
He added: "The gaffer did a great job last season and he's doing that still."