Spurs will face United at White Hart Lane.
King said: “It’s a massive game whenever you play the champions, a great game to be involved in.
“They have fantastic players throughout their squad and these are the games you want to be involved in, testing yourself against the top players.
“It’s a good challenge for us. We’ve not lost to the other three sides in the top four we’ve played so far and we can take confidence from that.
“It’s been close between us and United in recent years but that’s what makes them champions – they find a way of getting a result.
“That’s what has happened in the past but we’re on a good run now and we’re confident that perhaps now is the right time to get a result against United.”
