Bolton 1-0 West Ham
Jay-Jay Okocha was the hero as Bolton took a massive step towards Premiership safety while loosening West Ham's increasingly tenuous grip on their top-flight status.
Bolton went into the game just one place above West Ham but now have a six-point advantage over the Hammers, who have just four games left to try and scramble to safety.
It was a tense encounter that Bolton, sprinkled with experienced internationals, handled with greater composure.
While the home team attacked with purpose through the imperious Okocha and Youri Djorkaeff, West Ham surrendered possession far too often and seemed anxious in front of goal.
Okocha's stunning strike was in part due to poor finishing by the visitors, which allowed the Nigerian to run 40 yards on the break with the ball before unleashing a blistering shot from the edge of the area.
After conceding, the Hammers struggled to raise their game and it was not until the introduction of Les Ferdinand that the visitors were able to create the sort of pressure the situation demanded.
On the stroke of full-time the crushing sense of disappointment was too much for Ian Pearce, who was red carded for a horrible lunge on Bolton substitute Pierre-Yves Andre.
With so much at stake it was understandable that both teams started nervously.
Frederic Kanoute duffed a chip and Jermain Defoe fired straight at Jussi Jaaskelainen for West Ham, while Henrik Pedersen embarrassed himself with an air shot and Okocha blazed over for the home side after Ivan Campo had flicked-on a Djorkaeff corner.
Okocha almost punished the opposition's failure to clear their lines after 12 minutes but the Nigerian's 20-yard striker hit the post.
And Djorkaeff forced a good save from David James just after the half-hour mark with a well-struck shot from 18 yards.
With half-time looming Bolton's marginal superiority paid dividends with a goal from the mercurial Okocha.
Defoe's shot was blocked and the ball broke to the Bolton midfielder in the centre circle.
12 mins: Okocha's shot hits the post
38 mins: Okocha brilliantly scores
90 mins: West Ham's Pearce is sent-off
The Nigerian wasted no time in picking his way through West Ham's fractured defensive ranks before smashing home from 18 yards.
James saved again from Okocha and Bernard Mendy as Bolton looked to increase their lead before the break.
Chances were at a premium after the break, with much of the match played in the congested middle third of the field.
Hammers boss Glenn Roeder introduced Ferdinand and the veteran's knock-down fell to Kanoute, but the Frenchman's first touch was poor.
Another long ball was headed into Defoe's path by Ferdinand, but the young striker blazed wide as the Hammers finally created some pressure with time running out.
Okocha might have doubled his tally but, as in the first half, he shot over from the edge of the area.
The Nigerian was withdrawn with minutes remaining and Andre, his replacement, was hacked by Pearce, who was dismissed for the challenge.
The final whistle did not coincide with the end of the action, with an unsightly melee taking place in the centre circle.
Bolton: Jaaskelainen, N'Gotty, Bergsson, Laville, Charlton,
Mendy, Campo, Frandsen, Okocha (Andre 89), Pedersen,
Djorkaeff (Nolan 82).
Subs Not Used: Poole, Facey, Barness
Booked: Mendy, Laville, Campo.
West Ham: James, Johnson, Repka, Pearce, Brevett, Lomas, Cole,
Cisse (Les Ferdinand 65), Sinclair, Defoe, Kanoute.
Subs Not Used: Van Der Gouw, Hutchison, Dailly, Breen.
Sent Off: Pearce (90).
Booked: Johnson, Defoe, Lomas, Cole.
Referee: U Rennie (S Yorkshire).