David Moyes marked his return as West Ham manager with an impressive victory thanks to goals from Mark Noble, Sebastien Haller and Felipe Anderson.
It was a perfect performance from the home side who were well-deserving of three points, however it was easy for the Hammers against a Bournemouth side that struggled to get going all evening.
Story of the match
The second Moyes era began amidst a subdued atmosphere at the London Stadium, a lack of chances to report for either side with Pablo Fornals’ speculative curling effort the highlight of a dull opening 10 minutes.
It required a stroke of luck, but the home support was eventually spurred into life as West Ham took the lead with 18 minutes gone, Mark Noble’s driven effort taking a massive deflection off of Lewis Cook before trickling past Aaron Ramsdale in the Bournemouth goal.
The Hammers began to dominate following the opener, and it didn’t take long for them to find another, a quality acrobatic effort from Haller guiding home Ryan Fredericks’ cross to make it 2-0, the centre-forward demonstrating superb athleticism and skill to double the home side’s advantage.
Eddie Howe’s team showed some glimpses on the counter-attack, and persisted in trying to play out from the back, but West Ham ‘keeper Lukasz Fabianski was largely untested throughout the majority of the first-half, and things went from bad to worse on 35 minutes.
Noble showed guise to draw contact from Harry Wilson as he burst into the penalty area, referee Graham Scott pointed to the penalty spot, and after a VAR check, West Ham’s captain converted for his second of the night to give his team a 3-0 lead.
The third goal was enough for some travelling fans as they began to make their way for the exits, the Cherries looking very poor all-round and displaying why they will be facing a battle to avoid the drop this season.
Moyes would have been delighted by his side’s first-half performance with the hosts deserving of their comprehensive lead, the attempt to press high up the pitch a notable difference from the team’s performance under former boss Manuel Pellegrini.
Bournemouth were first out after the break with Junior Stanislas and Ryan Fraser replacing Diego Rico and Harry Wilson, but Howe's half-time changes did not have the desired immediate effect as it was the hosts that looked most likely to grab the fourth goal of the game.
It was Pablo Fornals who almost made it 4-0 shortly after the restart, a last-ditch interception preventing the Spaniard from converting Haller's cross at the far post.
However, with 66 minutes on the clock, Anderson glided past Simon Francis and slot his effort underneath Ramsdale from close-range to pile even more misery onto Bournemouth.
The visitors struggled to create anything of significance, with the home side looking defensively resolute for the first match in quite some time, each man contributing to a very good team performance.
It appeared that West Ham were going to be reduced to ten men when Aaron Cresswell was shown a red card for a heavy challenge on Fraser, however, his dismissal was rescinded following a VAR check, and the left-back remained on the pitch.
With 15 minutes remaining, the away side finally begin to build some momentum and Dominic Solanke almost headed home a consolation goal, but luck did not appear to be on Bournemouth's side, and the forward's effort was kept out by the post.
Moyes' men looked comfortable in possession throughout with the home supporters cheering every pass as the game drew to a close, and they almost scored a very well-worked goal with 10 minutes remaining, Fornals forcing a good save from Ramsdale after a flowing passing move.
Fraser went close late on after he was played through on goal by Wilson, but the Scotsman was unable to convert, and Fabianski saved with ease to maintain the clean sheet, and it finished 4-0.
New-manager bounce in full effect
Life under David Moyes (take two) got off to the perfect start with West Ham racing into a 3-0 half-time lead before consolidating all three points through Felipe Anderson's second-half finish.
The Hammers looked rejuvenated, pressing Bournemouth high up the pitch throughout, and succeeding on numerous occasions.
Felipe Anderson looked like a player reborn, and Mark Noble, with two goals to his name, turned in a stellar performance.
Hammers must use momentum
West Ham's next league fixtures include an away trip to Sheffield United before a home fixture against David Moyes' former side, Everton.
After an awful run of form that saw Manuel Pellegrini lose his job, the Hammers must use their emphatic victory against Bournemouth as momentum to propel the side away from the relegation zone.
Cherries prove relegation credentials
Bournemouth found themselves 3-0 down at the break and deservedly so.
There was some limited improvement after half-time, but the Cherries looked like conceding every time West Ham went forward, and struggled to pose any attacking threat of their own.
The next league game is a relegation six-pointer against Nigel Pearson's in-form Watford side.