Southampton delivered a severe blow to Manchester City's English Premier League title defense by beating the champion 3-1 after mistakes by Joe Hart and Gareth Barry on Saturday.
Jason Puncheon put Southampton ahead after seven minutes and Rickie Lambert's fierce drive squirmed through the grasp of goalkeeper Hart, allowing Steven Davis to bundle in the second.
Edin Dzeko reduced the deficit as halftime approached, but a two-goal lead was restored early in the second half when Barry passed into his own goal unchallenged.
''I am disappointed with our performance. They deserved to win,'' City manager Roberto Mancini said. ''We didn't play well. We conceded a goal that I have never seen in my life ... I think it's our worst game in the last two or three years.''
Mancini rates City's title prospects now at ''10 percent, maybe.''
''We're missing Vinny (Kompany) and missing (Matija) Nastasic, and we have some players who are not in form,'' he said. ''They played really bad - without strength, without personality. I'm very disappointed in them.''
For Southampton, the result lifts the team six points from the relegation zone.
''We were absolutely superb today and got exactly what we deserved,'' Lambert said.
The opener came after Barry was dispossessed. Puncheon burst down the right flank and played through the unmarked Jay Rodriguez. Hart managed to deny the winger but the ball fell kindly for Puncheon, who slotted calmly into the net.
City was struggling to deal with Southampton's attacking intent in an opening 15 minutes in which a tame Sergio Aguero effort was all the visitors could produce.
They eventually began to settle but were soon rocked by a second Southampton goal in the 22nd.
Lambert collected the ball on the right and played a neat one-two with Puncheon, before cutting back and firing a shot that Hart let slip through from his midriff, allowing Davis to poke home.
''We looked for the early goal and looked to put them under pressure early and hope to capitalize on it,'' Lambert said. ''It worked perfectly. Then we went 2-0 up, which was even better.''
But City pulled one back in the 39th after Dzeko tucked home a cross from Pablo Zabaleta.
Southampton was annoyed that referee Martin Atkinson waved away Rodriguez's penalty appeal on the stroke of halftime after he was brought to ground in the area by Yaya Toure, captaining City on his return from the African Cup of Nations.
''I ran in and I think there was a little nudge, but the referee hasn't given it so we got on with the game,'' Rodriquez said.
And they were celebrating at the start of the second half.
A pullback from Lambert was inexplicably passed into his own goal by Barry.
The visitors were having to defend with all they had and hope for a chance on the counter, with goalkeeper Artur Boruc reacting well to palm away Aguero's strike.
But City was soon back on the defensive as Southampton held on for all three points.
