Bentley, 23, hopes to add some more goals to the hat-trick he scored against United 18 months ago. He said: "We've taken points off three of the big four and it will be nice to make it the full set.
"We'll only get two or three chances at Old Trafford but if we take them, who knows.
"We can go there and not concede. No one will expect us to get anything there - but we do."