Manchester United defender Chris Smalling has admitted that coming in direct competition with Jamie Vardy "is a bit of a nightmare", as he prepares for Saturday evening's trip to Leicester City.

Vardy has eight goals in 20 appearances in all competitions this season and boasts a decent record against the division's top sides, most recently netting from the penalty spot against Manchester City in the EFL Cup.

The England international revealed in his autobiography that compatriot Smalling is the toughest opponent he has come up against, and the feeling appears to be mutual ahead of this weekend's King Power Stadium showdown.

Speaking to United's official website, Smalling said: "He is [a threat]. I enjoy my tussles with 'Vards'. He is someone who is a bit of a nightmare for defenders because he is often ratting around and chasing with non-stop running.

"He runs in behind which, as a defender, is the hardest thing to deal with, but I will be looking forward to that battle and, hopefully, I'll be ready to keep him quiet.

"Leicester know what they are about. And I think, when you play Leicester, you know how they are going to play. You know their qualities and their wingers - Demarai Gray is coming into the team and Riyad Mahrez is in form as well.

"So those are the players we need to keep quiet and, when we get the ball, we need to make sure that we get at their backline."

Smalling has featured in each of the Red Devils' last 21 matches, starting 19 of those.