Mauro Zarate's double and a Gary McSheffrey penalty gave Birmingham a huge boost in their fight against relegation with a 3-1 victory over a poor Manchester City at St Andrew's.

Zarate put Birmingham two-up before Franck Queudrue was sent off in fouling Benjani and conceding a second-half penalty, which Elano tucked away to give City hope of forcing an equaliser.

But a dreadful penalty decision from referee Rob Styles when Sun Jihai and McSheffrey clashed in the City box minutes later saw the home side restore their two-goal lead and ensure a comfortable finish.

The result means Alex McLeish's side are now four points clear of the relegation zone, while City's faltering push for Europe now appears to have stalled completely.

With both managers sensing the chance to take all three points, the match started brightly and Benjani should have given City an early lead when he was cleverly played in by Elano, only for the Zimbabwean to hit the post with a scuffed effort.

But with City struggling to get moving in midfield, the home side started to get on top. Radhi Jaidi had a corner cleared off the line by Sun after the big defender had made good contact on his header from a McSheffrey corner.

Just after the half-hour, Richard Dunne's interception of a Seb Larsson through-ball looped just over his own crossbar, and Joe Hart was forced to tip Queudrue's amazing overhead kick over from the resulting corner as Birmingham cranked up the pressure.

But, moments after Larsson had narrowly failed to get on the end of an inswinging cross from the left at the back post, they eventually made the breakthrough as Dunne's lunge failed to cut out Queudrue's pass and Zarate out-sprinted Nedum Onuoha to finish smartly past the on-rushing Hart.

City had plenty of the ball after the restart, but their passing was still letting them down as they tried to work the ball into dangerous positions, and Birmingham made the visitors pay with a snap-shot second as Zarate slammed a low shot into the bottom corner from 20 yards after a fine piece of control from Mikael Forssell on the edge of the box.

But a couple of minutes later, City were handed a lifeline when referee Styles harshly ruled that Queudrue had brought down Benjani as the pair chased a ball into the box, sending off the defender and awarding City a penalty which Elano tucked home.

City boss Sven-Goren Eriksson turned to Felipe Caicedo and Geovanni as he tried to sharpen up the visitors' passing in the Birmingham half, although there was little sign of an improvement.

And any chance City had of cranking up the pressure in the final stages was snatched away by a frankly staggering decision from referee Styles, who awarded a penalty when Sun and McSheffrey clashed shoulder-to-shoulder in the box as they hunted down Larsson's cross.

Hart got a hand to McSheffrey's firm spot-kick but could not keep it out as the former Coventry man scored his first goal for the club to ensure there would be no nervous finish for the Blues' fans.

Alex Sharratt / Eurosport