Manchester City's Manager Roberto Mancini reacts during his side's English Premier League soccer match against Southampton at St Mary's Stadium in Southampton February 9, 2013. Image Credit: Reuters

Southampton: Roberto Mancini tore into his Manchester City flops and admitted the champions' title hopes are in tatters after Southampton claimed a shock 3-1 win at St Mary's on Saturday.

Mancini was furious as City delivered one of their worst performances of his reign in a match they desperately needed to win to keep the pressure on Premier League leaders Manchester United.

City were two goals down in 22 minutes, with England goalkeeper Joe Hart gifting Southampton their second with an embarrassing mistake.

Even when Mancini's men got one back through Edin Dzeko, a comical Gareth Barry own goal allowed Southampton to clinch their first win under new manager Mauricio Pochettino.

City remain nine points behind United but that gap will stretch to 12 if Alex Ferguson's team beat Everton at Old Trafford on Sunday and boss Mancini conceded they have virtually no chance of winning the league.

"It'll be very difficult to win the league. I use to be always be optimistic and want to be in this moment, but it's difficult," he said.

"I think we now have 10 per cent (chance of winning the title). I don't think United will drop 12 points."

Mancini's side have now gone three league games without a win and the Italian's frustration was clear as he launched a scathing attack on their tepid display.

"It was a really poor performance. Southampton were better than us. We conceded two goals which I didn't think a team like us could concede," he said.

"I've never seen our team concede goals like this. In the end we made two incredible mistakes. The performance was really poor. We played this game with only two or three players. Three versus 11 was really difficult.

"I was really disappointed with my players. When we perform like this I'm very angry.

"The players were away on international duty - that's not an excuse, but it is a reason. Some of our players came back on Friday and we played today. This made it difficult."