Two goals from Craig Bellamy and another spell-binding display from Robert Green helped West Ham United romp to a Boxing Day win over Portsmouth.

While some Hammers supporters may have foregone a trip to Fratton Park in favour of the post-Christmas sales, those who did head to Hampshire were treated to a fantastic festive performance from Gianfranco Zola's team. Young midfielder Jack Collison and striker Carlton Cole also found the net, while former United forward Jermain Defoe missed a vital first-half penalty for Pompey with the score at 1-1.

Victory extended West Ham United's unbeaten Premier League run away from home to five matches and will send Zola and his players into Sunday's home fixture against Stoke City in hugely confident mood. What made the success even more impressive was the fact that the Hammers - who were unchanged from last weekend's unlucky defeat by Aston Villa - had to come from behind to secure it.

Having hardly ventured out of their own half in the opening eight minutes, Portsmouth duly took the lead with a goal of real craft started and finished by Nadir Belhadj. The Algerian international, on loan from French club RC Lens, fed Defoe, who worked the ball wide to Glen Little. The winger's deep cross was controlled by Peter Crouch, whose instant cut-back was thumped past Green by Belhadj from ten yards.

Having gone ahead, Pompey grew in confidence but their advantage would last just 12 minutes. Calum Davenport - who retained his place with James Collins returning to the bench - with a volley, and Bellamy, with a curling free-kick, had both fired off target before Collison levelled matters. Mark Noble's quickly-taken free-kick found Cole inside the home penalty area and when the striker rolled the ball into the Wales international's path, his low side-foot shot found its way through the legs of both Bellamy and an unsighted David James on its way into the net. A minute later, the visibly lifted Hammers went close again when James mishandled Bellamy's low cross-shot.

For the remainder of the opening 45 minutes the game ebbed and flowed as both teams continued to create - and waste - presentable chance after presentable chance. With neither side able to stop the other from passing the ball almost at will, it was a miracle that half-time arrived with the scoreline still deadlocked at 1-1.

Defoe was Portsmouth's main villain, firing woefully wide from then penalty spot in the second minute of added time after Hammers captain Lucas Neill had been penalised for impeding Crouch. Earlier, the former United striker had seen a powerful left-foot shot fly narrowly wide, while Green also had to be at his brilliant best to repel acrobatic volleys from England colleague Crouch and Sean Davis.

At the other end, Noble should have done better after Bellamy had nicked a short backpass off James' toe. Having sidestepped the prone goalkeeper, the England Under-21 midfielder's chip was not high enough to clear Sol Campbell and the veteran defender was able to head clear. Thankfully for the travelling supporters who had made their way down the A3 on Boxing Day, their fellow east Londoner's miss would not prove costly.

At the break Julien Faubert was brought on for captain Neill, who had taken a knock in the first half, with Matthew Upson taking over as skipper. The Frenchman responded by producing one of his most confident performances for the club at right-back. The 25-year-old made one particularly fine interception to deny Defoe and will have taken great heart from his display.

Amazingly, the second 45 minutes were, if anything, even more incident-packed than the first. Portsmouth started the better and less than three minutes had elapsed when Green was called into action again, blocking Crouch's first-time shot following Sylvin Distin's buccaneering run and cross. Shortly afterwards, the tall striker wasted another opportunity, volleying well over from Belhadj's deflected centre. Pompey were looking the more likely to re-take the lead and, had it not been for Green producing four more fine stops to deny Belhadj, Defoe, Davis and, yet again, Crouch, the hosts surely would have done so.

Instead, less than 30 seconds after Green had done well to hold Crouch's 67th-minute volley, it was the Hammers who went ahead for the first time. Bellamy broke clear down the left before clipping the ball into Collison's path. The midfielder's shot cannoned back off the base of the far post, but  Cole was in the perfect place to gleefully tuck in the rebound to net his fifth goal of the season.

Three minutes later, history repeated itself. Less than a minute after rookie right-back Marc Wilson had headed Little's corner against the outside of the post, Bellamy had all but made the game safe for the visitors, racing clear of the Portsmouth defence on to Collison's long pass before smashing the ball into the roof of the net at the second attempt after initially being thwarted by James.

Having seen Defoe replaced by home manager Tony Adams, Bellamy put the icing on the Hammers' Christmas cake with seven minutes remaining. The move for United's fourth goal was created by substitute Luis Boa Morte, whose low cross was calmly slotted into James' bottom left-hand corner by the Wales captain. Behind the goal, West Ham's supporters burst into a festive rendition of 'Jingle Bells' and who could blame them?