West Ham United's bad luck at the Reebok Stadium continued as they went down to a 3-1 defeat to Bolton Wanderers on Tuesday.

An uncharacteristic error by Robert Green paved the way for the Trotters' victory just when it looked like the Hammers would take the game by the scruff of the neck.

Green was unable to hold on to the ball after Gary Cahill's shot had flicked off the head of Tamir Cohen, enabling Croatia forward Ivan Klasnic to slot into the unguarded net 13 minutes from time.

Defeat was tough on Gianfranco Zola's side, who looked to have grabbed a point through Alessandro Diamanti's stunning finish after Chung-Yong Lee had slotted the Trotters into a second-half lead.

Cahill's late header from a Ricardo Gardner corner rubbed salt into West Ham's already tender wounds.

No doubt buoyed by the 3-3 draw they secured against big-spending Manchester City on Saturday - a game in which Klasnic scored twice - Bolton were the better side before half-time, but a mixture of resolute defending and wayward finishing ensured the game was still goalless after 45 minutes.

West Ham's best chance of the opening half fell to Kieron Dyer, who raced on to Ilunga's pass before shooting too close to Jussi Jaaskelainen.

At the other end, Bolton were a constant threat. Just 35 seconds had passed when Kevin Davies robbed the returning Collison before seeing his low shot deflect narrowly wide off James Tomkins.

Seven minutes later, West Ham had Tomkins' centre-back partner Danny Gabbidon to thank after  the Wales defender positioned himself superbly to cut out Davies' attempted cross to the unmarked Klasnic.

An already physical affair threatened to boil over momentarily soon afterwards when Davies barged Green well after the goalkeeper had claimed the ball. The Bolton forward was booked for his challenge, while Klasnic was also shown the yellow card for raising his hands to Scott Parker's face in the ensuing melee.

Soon afterwards, Dyer was forced to head for the away dressing room with an apparent injury. The England man was replaced by the player he had replaced in the starting lineup, Junior Stanislas.

Bolton continued to carry the greater threat as the half wore on, with Fabrice Muamba, Zat Knight, Cahill, Cohen, Klasnic and Davies all going close.

The second half was equally keenly-fought, with Zola changing to a 4-4-1-1 formation in a bid to put the home side under more pressure.

The move nearly paid off nine minutes after the break. Green blocked Cahill's fierce shot with his legs, the ball rebounded to Diamanti, who fed Parker. The midfielder made 50 yards, skipping around two Bolton players before forcing Jaaskelainen into an acrobatic fingertip save.

The Finn was called into action again just past the hour-mark, when Diamanti found some space 25 yards out before curling a shot into the goalkeeper's grasp.

It was the home side who broke the deadlock, however, through South Korea winger Lee. The 21-year-old played a neat one-two with Klasnic before slotting the ball past Green as the clock ticked on to 65 minutes.

Bolton's lead lasted just four minutes, however, as Ilunga cut in from the left before finding Franco who, in turn, found Collison. The Welshman slid the ball sideways to Diamanti, who slammed the ball into the roof of the net

Just a minute later, Parker skimmed the top of the crossbar with a rasping 30-yard shot as West Ham went for a winner, only for Wanderers to hit them with a sucker punch of devastating proportions.

There appeared little danger when Cahill's deflected shot flew through to Green, only for the England stopper to drop the ball at the feet of the alert Klasnic, who gleefully converted.

With time running short , Zola threw on Manuel da Costa as an emergency striker in the closing stages, but it was Bolton who finished the stronger and wrapped up the three points a minute from full-time.

Green was forced to push substitute Chris Basham's shot aside. From the resulting Gardner corner, Cahill rose highest to head home at the far post.

West Ham United must now ready themselves for their return to the Boleyn Ground on Sunday, when Chelsea are the visitors.