The Dutch star has already bagged 16 goals in all competitions this season including 12 in 16 Premiership starts.
He boasts an incredible strike rate of 60 goals in 78 Premiership starts since moving to United from PSV in 2001.
"For a start it's a team effort," said defender Anthony, who will see more of the Dutch hitman than most on Sunday.
"It's a difficult one because he's one of the best strikers in the world and it's always a tough one against United when he's playing.
"On the day you need to stop the service to him. I know about him and I know his qualities around the box.
"You have to be aware all the time, especially when he's around the box becuase that's where he gets his goals. You can't switch off for a minute."
Anthony is confident the lads have moved on from the agony of a penalty shoot-out exit in the Carling Cup quarter-final against Middlesbrough on Wednesday.
"We're up for it," he insisted. "The lads are good spirits and we were unfortuate. We should have won it in normal time.
"You have to move on. This is an important game and we have to be ready for it, not thinking about what happened against Middlesbrough."
The question is simple enough - how do you stop Ruud Van Nistelrooy? Anthony Gardner is planning to do just that on Sunday.