He will be named North-East Footballer of the Year tomorrow night and his stock is rising rapidly.
O'Neill said: "He's playing brilliantly for us and here is the place for him. But it doesn't stop big teams coming and hovering around.
"I've been lucky in my career to have played in front of two unbelievable keepers in Pat Jennings and Peter Shilton and he's got a similar approach.
"When Jennings felt he had a point to prove, then he was unbeatable - and I feel Mignolet has this."