Manchester United midfielder Michael Carrick rates Chelsea as their biggest rivals.
The two teams meet later today.
Carrick told MUFC: "They'd won the league twice when I first joined and when I came they were the main rivals for the title. Since then it's been nip and tuck and we've both won things.
"You've had Arsenal and Liverpool challenging some years and of course Manchester City have come in as well, but certainly over the last 10 or 12 years Chelsea have been right up there."