West Ham United produced an excellent second-half performance to blow Huddersfield Town away and earn just their second Premier League away win of the campaign.
Joe Lolley's terrific solo goal had pulled the Terriers level after the midfielder was involved in a defensive mix-up with Jonas Lössl which allowed Mark Noble to put the Hammers ahead on 25 minutes.
But Marko Arnautović's stunning skill allowed him to put West Ham back ahead just 11 seconds into the second half before the Austrian played his part in both goals of Manuel Lanzini's quick-fire double to put David Moyes' men 4-1 up on the hour.
West Ham's intensity relented but they saw out a comprehensive win at the John Smith's Stadium to leapfrog Huddersfield into 11th and provide further proof of their progress under Moyes.
This was the former Everton and Manchester United manager's 200th win as a Premier League boss with United legend Sir Alex Ferguson, one of the other three to reach that milestone and the man who recommended Moyes as his successor at Old Trafford, watching on from the director's box in Yorkshire.
Lössl and Lolley gift Hammers the opener
The game's opening stages were high on endeavour and desire but short on quality in an expectedly physical and keenly-contested affair until Huddersfield handed West Ham a gift-wrapped opening goal.
Lössl attempted to play his goal kick short to Lolley, who was immediately swarmed by both Arnautović and Noble, allowing the skipper to run free on goal and slot in at the near post.
But Huddersfield improved after going behind, their chief threat coming via crosses into the box from wide positions - though no-one could rise to Tom Ince and Rajiv van La Parra's inviting deliveries.
Arnautović puts Hammers back ahead after Lolley leveller
David Wagner's side lacked the kind of creativity to carve open the opposition back-line and required a moment of individual brilliance to equalise as Lolley made amends for his part in West Ham's opener.
The midfielder received the ball from Aaron Mooy as Huddersfield countered down the right and jinked past Noble into the box to then curl a sublime left-footed effort inside the far post.
But their hard work was undone inside 11 seconds of the restart as Arnautović - so sharp on his return from injury - scored his fifth goal in as many top-flight matches.
Cheikhou Kouyaté helped send a long ball forward in towards the club-record summer signing, whose two marvellous mid-air touches allowed him to flick the ball over Tommy Smith and free up space in the area as he rifled low through Lössl.
Lanzini at the double as visitors run riot
West Ham almost scrambled in another immediately after from Aaron Cresswell's corner, but Mooy twice hacked clear off the line after Angelo Ogbonna had headed goalwards.
But the Londoners earned their third before the hour mark as Lanzini - moments after an audacious attempt to beat Lössl with a rabona shot - kept his cool to fire in low from Arnautović's pass.
Five minutes later it was 4-1 as West Ham got caught on the counter, Arnautović released by Kouyaté down the right. He burst towards the box where he found Lanzini to lash high into the top corner.
Huddersfield debutant Alex Pritchard's free-kick almost deflected off Jonathan Hogg to beat Adrián as the hosts sought a comeback, but otherwise they never looked likely of panicking the visitors.
Wagner's have now endured their longest run without a win this season and sit 13th, four points above the relegation zone with 18th-placed Stoke City facing United on Monday night.
Lanzini and Arnautović lead the charge
No player has benefitted more from Slaven Bilić's departure and Moyes' subsequent arrival than Arnautović, whose six goals and three assists have all come in his last seven league games.
Following an underwhelming start at the London Stadium, the £25 million attacker is truly a player reborn under Moyes and he relished the task of leading the line here in a 3-5-1-1, slightly ahead of Lanzini.
"Of course I want to show the club that they didn't pay so much money for nothing," he said recently, expressing a desire to become this West Ham team's talisman.
And with his current form he is certainly staking his case to become the kind of leading figure that they have missed since Dmitri Payet left.
His strike to put the Hammers back in front was truly sublime before he showcased more of his graft and quality to twice tee up Lanzini for the away side's third and fourth goals.
Without Andy Carroll and with the unfavoured Javier Hernández demoted back to the bench, Arnautović and Lanzini dove-tailed to great effect and were by far Moyes' most threatening attacking outlets.
Even in the first half the pair combined as if on a different wavelength to everyone else on the pitch and consistently looked capable of opening the hosts up, even though Arnautović had missed the last two games with a tight hamstring.
But their combination play truly tore Huddersfield's back-line to pieces in the second period through their pace, directness and close control as they interlinked and interwove.
Both players were undoubtedly helped by Huddersfield's continual mistakes but rightly earned rapturous applause from an ecstatic away end when later subbed off.
Outside of the big six, no team has claimed more points than West Ham in the last six games - with three wins, two draws and a single defeat - and having Arnautović and Lanzini on such form will be a monumental aid if such a revitalised run is to continue.
Terriers' standards slipping
Huddersfield are now winless in their last five Premier League games, but more worryingly - they have claimed just two points from an available 12 in their last four home outings.
The Terriers were the surprise package at the very start of the season when the newly-promoted side suffered just one defeat in their first six top-flight games, their first season in the highest division since 1971-72.
That run was underpinned by their defensive strength, keeping four clean sheets and conceding more than once in a single game only to West Ham - who inflicted the Terriers first defeat upon them in September.
But since that unbeaten run Huddersfield have struggled for momentum, failing to build back-to-back victories and suffering several heavy defeats.
A recent run of draws demonstrated their ability to grind out results as they embarked on their best unbeaten run since the start of the campaign, but some of those results were underwhelming. Clashes with Stoke and West Ham were handed the all-important 'six-pointer' status and have now yielded only one point.
They have collected 16 of their 24 points on home soil but as well as such disappointing results, they drew to Burnley and lost to Chelsea and have now not won in front of their own fans since December 12.
The frustrations at Huddersfield's lack of creativity - with £12 million debutant Pritchard unable to have an impact after being introduced at 4-1 down - grew louder throughout the afternoon as they created few chances, their goal a product of individual brilliance with their only other moments of excitement some teasing crosses.
Huddersfield are not lacking in effort or commitment but their struggles in the final third, allied with their drop in defensive performances, has meant that they hover dangerously above the relegation battle.
That said, this was a rare blip from Huddersfield - who are not used to committing such costly errors and have only lost at home to Manchester City, Tottenham Hotspur and Chelsea before this.
Yet even still Wagner must arrest his side's falling standards, defensively and in front of their home fans, with their back-line and home form pivotal if they are to maintain their points cushion and crucially, their Premier League status.