City scored only through Edin Dzeko at the end of the first half as Roberto Mancini\'s side slumped to a third winless game.
London: The English Premier League trophy slipped further from Manchester City's grasp after the champion lost 3-1 at Southampton on Saturday and gave Manchester United the opportunity to surge 12 points clear.
City's calamitous night on the south coast was summed up at the start of the second half when Gareth Barry put the ball into his own net to give Southampton its final goal.
A blunder by City goalkeeper Joe Hart in the first half allowed Steve Davis to net Southampton's second after Jason Puncheon's opener.
City scored only through Edin Dzeko at the end of the first half as Roberto Mancini's side slumped to a third winless game.
The nine-point gap at the top will be extended if leaders United beat Everton on Sunday.