Grant vows to battle after latest body blow

West Ham are truly sick of the sight of Birmingham. The London club's Wembley aspirations were cruelly ruined by Alex McLeish's men in the Carling Cup semi-finals less than a fortnight ago. And yesterday Birmingham condemned them to a hugely significant defeat in the relegation battle.

This result sent West Ham tumbling back down to the bottom of the table. Birmingham had started the day equal on points, but with two games in hand on Avram Grant's men, so West Ham desperately needed a win to stay in touch. Nikola Zigic's match-winning header, midway through the second half of a scrappy encounter, is a memory that will return to haunt West Ham if they drop out of the Premier League.

"This situation is not easy but it will be a battle until the end," said Grant, on an unhappy 56th birthday. "There are not so many points between the teams at the bottom. But I was disappointed with the tempo of our game."

It was a sloppy start to the game, with stray passes aplenty, as both sides took a cautious approach. Birmingham had the first attempts at goal, with David Bentley and then Craig Gardner both missing the target with strikes from just outside the 18-yard box. The home side responded with similar efforts from Robbie Keane and Victor Obinna.

West Ham looked livelier in the 31st minute as Gary O'Neil whipped in a testing delivery that Stephen Carr cleared into the path of Mark Noble, whose shot was too powerful and cleared the crossbar. That roused the visitors who promptly created the best chance of the half as Lee Bowyer swung in a cross from the left that Roger Johnson headed over from eight yards. Obinna was next to threaten, sending in a swerving cross at pace that Johnson had to throw himself at to head clear.

Shouts for a penalty were ignored when Obinna crossed for Lars Jacobsen, who struck the ball at Liam Ridgewell's arm. Soon afterwards, Keane advanced into a dangerous position before firing over.

West Ham kept up their momentum early in the second half, but Birmingham gave them a warning in the 51st minute when Bentley lofted the ball towards the back post, where Zigic headed into the side-netting. Manuel Da Costa – who replaced the injured Matthew Upson at half-time – and fellow defender Wayne Bridge clearly did not take note, as they allowed Zigic to head Birmingham in front in the 63rd minute. Upson had done a decent job of monitoring Zigic in the first half so the departure of the England centre-back was felt acutely.

The goal came from a free-kick, cleverly won by Bentley who drew a foul from Noble. Substitute Sebastian Larsson chipped the set-piece, from the left of the penalty area, to the back post where Zigic connected.

"Zigic has upped his game," said McLeish. "He's a bit like [Peter] Crouchy – he used to be awkward but now can be impossible to play against."

It was ironic that the man to supply the winner was Larsson. The Swede had been brought on as part of a defensive change of formation as Birmingham reverted to a 4-5-1.

West Ham came inches away from an equaliser following a free-kick of their own, taken by Bridge. It was met by a weak header from Da Costa but the loose ball fell kindly into the path of Demba Ba, whose shot from a tight angle struck a post.

Da Costa made himself more useful when he tested Ben Foster with a powerful long-range drive that the Birmingham goalkeeper pushed away. Carlton Cole then wasted a late chance, directing his effort wide.

Match facts

Subs: West Ham Da Costa (Upson, h/t), Cole (Piquionne, 59), Ba (Keane, 75) Unused Boffin (gk), Faubert, Kovac, Sears.

Birmingham Larsson (Jerome, 57) Unused Doyle (gk), Murphy, Davies, Fahey, Beausejour, Phillips.

Booked: West Ham Noble, Obinna, Da Costa Birmingham Foster.

Man of the match Bentley Match rating 6/10.

Possession West Ham 55% Birmingham 45%.

Attempts on target West Ham 9 Birmingham 9.

Referee C Foy (Merseyside) Att 32,927.