Chelsea captain John Terry has fired a warning to rivals Manchester United.
Terry's side trail Man Utd by five points
Terry's side struggled to beat Newcastle on Wednesday and trail United by five points after 17 league games.
But the England skipper said: "They are probably playing the best football they can play at the moment. They've had very few injuries so far.
"Whereas we know as a team we've got another level to go to. We need to take the game to teams and then no-one can live with us."
Terry's team overcame a dogged Newcastle side thanks to a second-half match-winner from substitute Didier Drogba.
And he added: "We must go on a run of games and keep winning.
"We must keep the pressure up. Christmas is a difficult period. United have got tough games. We must just keep winning and keep on like we know we're capable of."
Drogba was injured. A normal player, with a normal attitude would not have played
Chelsea boss Jose Mourinho
Chelsea struggled to break down Glenn Roeder's makeshift side until Drogba, a half-time replacement for the injured Ricardo Carvalho, slid the ball home after Andriy Shevchenko had miscued his shot.
Drogba, nursing a hamstring injury, started on the bench along with Andriy Shevchenko.
But unlike Drogba, the Ukrainian striker had been dropped by manager Jose Mourinho.
Mourinho added: "I make decisions from my analysis. I took him out of the team because I felt the team needed different qualities.
"With Salomon Kalou and Arjen Robben, I get different qualities. So we decided to make some changes and Shevchenko was out.
"I think (Shevchenko) took it as a professional. He was not happy but behaved properly. He came on when I decided and did well for the team."
Mourinho left Drogba in the dugout until half-time because of his injury problem. He added: "Drogba was injured. A normal player, with a normal attitude would not have played.
"So I was trying to explain to him the best decision was to save him. If the result was positive at half-time we would not have played him.
"But I felt we needed him at half-time. His attitude in the game and the way he worked for the team meant he was very important for us. He is one of the top players at the moment."