Chelsea manager Jose Mourinho has refused to rule Manchester United out of the Premier League title race.
United have struggled to adapt to life this season under new boss David Moyes, who replaced Sir Alex Ferguson in the summer.
The Red Devils currently sit seventh in the table, and are 11 points adrift of leaders Arsenal going into Sunday’s clash with the Blues at Stamford Bridge.
However, Mourinho feels last season’s champions still have a chance of retaining their title come May.
“I've not written them off, no,” he said. “I think, if you look at the table, obviously Arsenal and Manchester City are the top two teams. I repeat: Man City have different ammunition for such difficult work for everybody. But we are not far. Liverpool have a fantastic opportunity to do it. It's almost unique, the fact they're not playing in European competitions.
“And United are United. 11 points from the leader is quite a lot, but they'll push all the way. The way this league is at this moment, for all the big teams, the first objective is to secure the top four. It'll be hard for everybody to do it.
“Read the match programme -- my notes. And on Sunday you can read it. I start by saying we don't play a team who are 11 points behind the leaders. We play against the champions. We play against Manchester United. This is how I feel.
“I've been in the game for too long. I've played dozens of derbies and classic matches, matches between the big teams, and this is what experience says. More than that, many times on many occasions, the team that looks to be in the most difficult situation is the team that appears stronger in that match. That's why I consider this game especially dangerous for us.”
Mourinho claimed earlier this week he has “inside information” that United are unhappy with their current plight following Moyes' appointment last summer.
However, the Portuguese has since moved to back the under-pressure Scot to eventually be a success at Old Trafford.
“I said before, I don't think there's a reason to have sympathy,” he said. “He has a fantastic job and is very, very stable. The club gave him an incredible trust when they chose him to be the next United manager after Sir Alex. They believe in the power of the manager, the support of the manager.
“It's not because they had a couple of bad results and aren't top of the league, as they normally are. There's no reason for David to be in trouble. He's very stable. He will have at least the time of his contract to build a team, to reach success, and to be there for many years. I don't think he needs sympathy. He has a fantastic job and no problems.”