The 35-year-old has this season continued to impress for United at the highest level.
“I don’t know what more there is to say about him,” said the United boss.
“It’s not a matter of defying age with him because there has been no deterioration in his game at all and it’s remarkable.
“It’s down to how he has lived his life, how he has looked after himself and done the right things and his form is just as good as it was last year.”
