BY the time Manchester City gets its game against Chelsea going on Sunday, the Barclays Premier League (BPL) champions could be staring at a seemingly insurmountable 15-point gap between themselves and current leaders Manchester United.

Failure to defeat the third-placed Blues at the Etihad Stadium and Roberto Mancini could see his already precarious position as City manager become even more tenuous.

This wasn't quite the script that City's billionaire bosses from Qatar had expected for this season, especially after their heavy investments reaped handsome dividends last May when Mancini led the club to a first league championship in 44 long years last May - at the expense of neighbours United, no less.

Put simply, things have gone all pear-shaped for City's quest to retain its BPL crown and prevent the Red Devils from winning a 20th title with just 11 games to play after this weekend's fixtures are completed.

As things stand, Manchester United is threatening to run away with the BPL trophy.

Alex Ferguson's men are at relegation-haunted Queens Park Rangers later tonight and, barring a major upset, should leave London with maximum points to pile the pressure on City. But such is the unpredictability of the BPL that shock results occur almost every other week. Just a fortnight ago in its last league match, City hit the self-destruct button in a 1-3 loss to strugglers Southampton.

Mancini was so disgusted with the performance that he stormed out of the stadium at full time without even speaking to his players. Chelsea, sitting four points below City, hasn't had much to shout about either this season but caretaker manager Rafael Benitez feels his side is hitting form at just the right moment to finish the season on a strong note.

The Blues face an FA Cup quarter-final at Manchester United next month and are still in the Europa League hunt after a battling 2-1 aggregate win over Sparta Prague on Thursday night.

Benitez himself knows that he can't afford any more slip-ups or he can kiss his hopes of getting the manager's job full-time goodbye. Chelsea's wealthy owner Roman Abramovich is merciless when it comes to wielding the axe, and Benitez's chances are already remote given his unpopularity with the fans at Stamford Bridge.

So what was once earmarked on the fixture calendar as a potential BPL title-decider has now morphed into a battle to secure second spot in the table, but both clubs, City especially, will hope for a miracle in trying to overhaul United.

One only has to look back to last season when City overcame an eight-point deficit with only six games remaining to snatch the trophy from United's grasp by virtue of a better goal difference.

The Red Devils, however, appear to have learnt from their past mistakes and are in ruthless form at the moment. After returning from Spain with a credible 1-1 draw against Real Madrid in the Champions League last week, United advanced to the last eight of the FA Cup on Monday by beating Reading 2-1.

The trip to QPR, a team seven points from safety, represents a potential banana skin for Ferguson's side. Manchester City laboured to a goalless draw at Loftus Road last month, and Mancini can only pray that United somehow stumbles as well.

At this late juncture, however, even divine intervention may not be enough for City.