LONDON (AP) -Winning the Premier League title in the final seconds of last season seemed to make the success even sweeter for Manchester City.
The club, though, needs to stop making a habit of unconvincing performances if it is to defend the trophy.
Going into the 10th league match of the season on Saturday at West Ham, City has shown its ruthless attacking only once so far when Sunderland was beaten 3-0.
And adding to uncertainty at City, manager Roberto Mancini said Friday that he was considering leaving before signing a new five-year contract in July.
"I was very close with seven or eight teams but I prefer to stay here," Mancini said. "I have worked well here for three years.
"If someone thinks we didn't do a good job - we won three trophies in two years. I am very happy we worked well. Now, the next three or four years will be very important for us."
But looking at the standings, it wouldn't appear that City has any problems, sitting unbeaten in third, only a point behind leader Chelsea.
"I believe in this squad," said Mancini, whose team is close to exiting the group stage of the Champions League for the second straight year. "We have time to improve and build a team."
On Saturday, West Ham manager Sam Allardyce will be hoping his team can exploit the defensive frailties of a side that has already conceded 22 goals in all competitions this season.
"I'm surprised (by City's start) but yet again there have been a few changes and a few players he has lost through injury and that disrupts what was his renowned back four for last season," Allardyce said. "(Mancini) has tried a different style, a different system. He has lost (Nigel) de Jong who used to give them that protection."
But a victory at West Ham could put City at the top of the Premier League if Chelsea and United both fail to win on Saturday.
Chelsea plays at Swansea fresh from losing its unbeaten start last weekend in an acrimonious match against United that dragged the game into yet another racism controversy. The Football Association and police are investigating allegations, initially reported by Chelsea, that referee Mark Clattenburg directed a racial insult at midfielder John Obi Mikel.
United could be in for another hostile match this weekend, with striker Robin van Persie potentially facing abuse from Arsenal fans on Saturday when he faces the London club for the first time since leaving in August.
The Netherlands international, who spent eight years at Arsenal, has already scored nine times in 12 appearances for United.
"The fact he has played in England makes it easier to go to another English club," United manager Alex Ferguson said. "It has been very satisfying for us. It has been a fantastic start and hopefully he keeps it going."
But Ferguson doesn't expect a repeat of United's 8-2 victory over Arsenal last season at Old Trafford - when Van Persie was an opponent.
"There is no point living in the past, we have just got to look forward to tomorrow," Ferguson said. "It could be a way of motivating Arsenal."
Arsenal is sixth, two points behind fourth-place north London rival Tottenham, which hosts Wigan on Saturday.
"No disrespect to Wigan, but out of the (next) three, this is the easiest game," Tottenham defender Kyle Walker said. "We want to get a good run into Wigan and then hopefully that will give us momentum to get to City and then hopefully after the international break we can go to Arsenal and get the three points there."
Liverpool captain Steven Gerrard should hit a landmark in his career on Saturday, with the midfielder due to make his 600th appearance for the club against Newcastle.
The 12th-place Reds are in need of a victory after being held to a 2-2 draw by Everton last weekend, and manager Brendan Rodgers is already looking ahead to January when he can strengthen the squad.
"We'll have funds," Rodgers said. "I'm in talks with the owners at the moment along with our recruitment team. We know we need to reinforce the group, so that's something that is ongoing.
"The priority is to get players into the building. Our squad is very small, very thin on the ground."
Neither Queens Park Rangers nor Reading have won this season and sit in the relegation zone along with Southampton, which is at West Bromwich Albion on Monday.
Also Saturday, Everton will try to move up from fifth with a win at Fulham, Norwich hosts Stoke and Sunderland takes on Aston Villa.