Jose Mourinho has yet to taste defeat in nine games at the Stamford Bridge helm and his team appears rapidly to have acquired their manager's occasionally breathtaking self-assurance.

On Wednesday even a fan from his former club Porto spitting in his face did not faze Mourinho and he has brushed off the charge that his side are boring with equal disdain.

"What for me is absolutely amazing is the way my big players play as a unit, play for the team, play for a result," Mourinho said.

"That's the reason why over nine matches nobody has beat us."

Liverpool, in contrast, are without their two best players from recent years -- striker Michael Owen to Real Madrid and midfielder Steven Gerrard to injury -- and have made a patchy start under Spanish coach Rafael Benitez.

Tuesday's 1-0 Champions League defeat by Greek side Olympiakos Piraeus was their fourth loss in seven matches.

Ten points from their opening six games in the Premier League, though, is no disgrace and Liverpool won 1-0 at Stamford Bridge last season.

Benitez's side have struggled on their travels and have developed a habit of conceding headed goals, a fact that will have been noted by the likes of Didier Drogba and John Terry in the Chelsea side.

"It is worrying that our away performances are so different from the games at Anfield and we have to work hard to change that," Benitez said.

But insisted his overhaul of Liverpool should not be judged for another two or three months.

Benitez said he was finding it hard to make changes at the club due to international breaks and expected his team to find form once next week's round of World Cup qualifiers is over.

"It is difficult because we have a lot of international games now."

"If you have six weeks without all the international games and you train all the week perhaps you can see more things.

"But if you need to start every 15 days preparing the marking or movement once again it's more difficult.

"We know this is the situation and perhaps in two or three months we will see better things."

Benitez believes last week's 3-0 win over Norwich proves Liverpool have the players needed to turn the club around after the loss of Owen and Gerrard.

"We know what to do. We have the ideas, " he said, adding: "The only thing is other teams can be more aggressive and you have to know what to do depending on the opposition."

In Sunday's other match, Wayne Rooney will do well to improve on his remarkable debut for fifth-placed Manchester United if Alex Ferguson selects him for his league debut against Middlesbrough at Old Trafford.

The 18-year-old's dazzling performance against Turkey's Fener-bahce in the Champions League was an indication of United's firepower with Alan Smith, Ruud van Nistelrooy and Louis Saha also vying for places in attack.

Middlesbrough manager Steve McClaren, though, will have been heartened by United's poor defensive organisation against the Turks.