Bobby Zamora made an immediate impact on his debut as West Ham produced a magnificent second-half fightback to beat brave Bradford in Nationwide Division One.

The striker, who joined the Hammers on Monday as part of the deal which saw Jermain Defoe move to Tottenham, was introduced as a half-time substitute with Bradford leading through Peter Atherton's 35th-minute goal.

Zamora needed just 20 minutes to open his account and he then turned provider as Marlon Harewood grabbed a 78th-minute winner to give West Ham's promotion hopes a massive boost.

The afternoon had begun badly for the Hammers when Matthew Etherington was injured during the warm-up and was replaced in the starting line-up by Jobi McAnuff, who was making his debut following his move from Wimbledon.

Bradford welcomed back playmaker Nicky Summerbee from suspension and he was involved in the first chance of the game as his third-minute corner picked out Alun Armstrong - but his header was superbly saved by Stephen Bywater.

At the other end Nigel Reo-Coker tested Bradford goalkeeper Alan Combe with a left-foot shot before Armstrong again went close, forcing Bywater into another impressive fingertip save.

The deadlock was almost broken in the 13th minute when Reo-Coker struck the woodwork with a right-foot shot but Gareth Farrelly, Ronnie Wallwork and Armstrong all went close for the home side before they went ahead.

West Ham's defence failed to deal with a long punt upfield and the ball dropped to Atherton, who fired a right-foot shot past Bywater from 17 yards for his first goal since March.

Hammers boss Alan Pardew reacted by making a double substitution at the break, with Zamora replacing Brian Deane and McAnuff going off for former Wimbledon team-mate Adam Nowland.

The visitors immediately looked a different side and Nowland almost made a dream start when his brilliant 20-yard volley produced an equally good save by Combe.

Zamora also went close with a volley as Bradford's goal came under increasing pressure and the former Brighton striker grabbed a deserved equaliser in the 65th minute when he headed home Christian Dailly's cross from the right.

Hayden Mullins shot wide as West Ham looked for a second and their second-half pressure paid off in the 78th minute.

Harewood latched onto Zamora's pass and placed a low shot through the legs of Combe for his third goal in four games and his 19th of the season.

Bradford pushed in vain for an equaliser and almost snatched a point late on when David Wetherall's header from Gareth Farrelly's free-kick was saved by Bywater.

Bradford Combe, Francis, Wetherall, Gavin, Heckingbottom, Summerbee (Windass 71), Atherton, Wallwork, Farrelly, Gray, Armstrong (Branch 88).

Subs Not Used: Bower, Muirhead, Evans.

Booked: Wallwork.

Goals: Atherton 35.

West Ham Bywater, Mullins, Dailly, Repka, Harley, Harewood, Reo-Coker, Carrick, McAnuff (Nowland 45), Deane (Zamora 45), Connolly (Melville 90).

Subs Not Used: Shaaban, Ferdinand.

Goals: Zamora 65, Harewood 78.

Att: 13,078

Ref: M Halsey (Lancashire).