Luiz Felipe Scolari admits Chelsea must prove they are genuine title contenders by beating Manchester United on Sunday.

Chelsea have yet to beat one of their big four rivals since the Brazilian took charge at the start of the season, but Scolari knows that must to change at Old Trafford. Chelsea remain four points clear of United, but Sir Alex Ferguson's team will move above them if they win their games in hand.

"Every game is a test but if you lose three points against a direct opponent, you are in trouble," Scolari said. "We need to win all the big games now. We need to win because they are four points behind but they have two games in hand. We need to think about winning because then we will be in front of Manchester and it is in our hands."

A disappointing run of three wins in ten matches in all competitions, including an embarrassing draw with Southend in the FA Cup, has raised questions about Scolari's ability to deliver the success demanded by Roman Abramovich, the Chelsea owner.

Scolari insists he doesn't feel under pressure to meet Abramovich's high expectations and instead claimed that Sunday's game was the type of showpiece occasion that he came to England for. "I need to arrive in first position in every competition. If I don't arrive in first I have the board who say if I have done well or not," he said. "But there is no pressure. This is my job. I want to win and make Chelsea better.

"I like this game. I was thinking about this game when I signed for Chelsea. Some games are different. I think half of the world will look at this game. This not a derby but it's an exciting game for the players, the coaches and for the rest of the world.

"If you call some friends in China, Brazil, Korea or Qatar they will watch the game. They want to know what time it is on. Everybody wants to see it. It is very good for the players. They don't need any words for motivation. If they see the world talking about this game it is fantastic."

With so much at stake this weekend, Scolari is relieved to have John Terry, the Chelsea captain, back from suspension. The England defender missed three matches following his red card at Everton before Christmas and Chelsea have looked rudderless in his absence. "It is important for us," Scolari said. "He is a leader. He plays very well every time. I think the opposing players respect him."

Scolari isn't reading much into United's surprise midweek League Cup semi-final defeat at Derby as several of Ferguson's stars were rested at Pride Park. "They are playing very well," he said. "They have just won the Club World Cup in Japan. They have many good players and are a fantastic club."

After dropping so many points at home recently, Scolari is happy to be facing United away and he revealed he has changed the squad's training routine to help improve their home form. "Sometimes when you play at home it is more difficult than away," he said. "I don't know why. I try to understand and I have changed things this week to help for the future."

Meanwhile, Scolari has told Tottenham to forget about signing England midfielder Joe Cole. Harry Redknapp was understood to be monitoring Cole's situation at Stamford Bridge but the Brazilian is determined to hang on to the 27-year-old. Cole has 18 months left on his deal at the club and has yet to be reassured he will be given a new one.

When asked whether Cole will be at the club in the long term, Scolari declared: "Yes, he will. He is a fantastic player and important for the club and for me. He scores many goals and his future is here."