LONDON (AP) -Unbeaten but underwhelming, Manchester City is causing anxiety among club officials and fans following the stuttering start to its Premier League title defense.
After winning only two of its opening five league matches, Robert Mancini's team has slipped four points behind leader Chelsea.
The match at Fulham on Saturday comes after City's defensive deficiencies have already been exposed on the road, having drawn both away matches.
"The beginning of the season is difficult and a lot of clubs are conceding goals," City defender Maicon said. "But I know that Roberto is very focused on it. He wants to improve and we have to improve quickly because we can't afford to have any more distance between us and the teams at the top of the league."
It's not only in the league that City is struggling, having lost in the Champions League at Real Madrid last week followed by an early exit from the League Cup on Tuesday.
"We need to work with our defenders because they don't work well at this moment," Mancini said. "When the situation is like this we have to understand our mistake and do our best for the future."
Maicon is sure that Mancini will be able to halt the slump, after also playing under the Italian at Inter Milan.
"He can get passionate but that is the way he should be," Maicon said. "If he gets angry he reminds everybody of the standards required. There is a minimum requirement that is always there. The players know they have to perform at that level."
Setting the pace at the moment is Chelsea, which has been barely troubled in cruising to top spot, apart from a draw at Queens Park Rangers.
Chelsea faces the first real test of its credentials on Saturday at fifth-place Arsenal, however, after having taken only a point off its London rival last season - even with the now absent Didier Drogba up front.
"I don't know how much Chelsea miss him, but we don't miss him! He did a lot of damage against us in every game," Arsenal manager Arsene Wenger said. "He has that quality and even when he was on a bad day for 80 minutes, he didn't give up and kept his focus and his desire to be efficient."
Another Chelsea slip-up against Arsenal could allow Manchester United to claim top spot, although the 19-time champions are short in defense for Saturday's home match against Tottenham.
Manager Alex Ferguson is down to two fit senior central defenders - Jonny Evans and Rio Ferdinand - after Nemanja Vidic joined Phil Jones and Chris Smalling on the injury list this week.
But there was encouraging news for Ferguson in Wednesday's League Cup win over Newcastle, with Wayne Rooney returning after a month out because of a gash to his right thigh and Darren Fletcher making his first start for 10 months as he battles to overcome a chronic bowel complaint.
"It was fantastic to have both Wazza (Rooney) and Fletch (Fletcher) back," United midfielder Tom Cleverley said. "Fletch is a big-game player who can bring positive things to any squad in the world, and Wazza came back and put in a great performance.
"We've been a bit unlucky with injuries but that's what we've got a squad for - as players get injured, others are coming back."
Despite those injury problems, United still ended its five-year wait for a win at Liverpool last weekend, prolonging its northwest rival's worst start for more than 100 years.
Brendan Rodgers' side has collected just two points from five matches, with only Queens Park Rangers and Reading keeping Liverpool off the bottom of the standings.
Defender Daniel Agger isn't panicking yet, backing Rodgers' passing and pressing philosophy to thrive eventually at Anfield. Ntex up, though, is a match on Saturday at Norwich.
"I like the manager's system and his style of football," Agger said. "It's the kind of system I like to play ... I see signs every day in training and in the game that we are going the right way. We need to be a little bit more clinical.
"The most important thing is to get the results but if you can do that - and at the same time play with a good style of football, good possession and aggression - that's a bonus."
The surprise teams in the top four at this early stage are Everton, which is at Southampton on Saturday, and West Bromwich Albion, which plays at Aston Villa the following day.
Also on Saturday, bottom-place Reading hosts Newcastle, Stoke takes on Swansea, and Sunderland faces Wigan.