David Unsworth's last game as Everton caretaker manager ended in victory as Wayne Rooney's hat-trick gave the Toffees a vital three-points in front of the onlooking Sam Allardyce.
Recalled to the starting lineup following a mixed opening to the season, summer signing Rooney put Unsworth's men ahead at the second time of asking after his penalty had been saved by Joe Hart.
The same player made it 2-0 shortly after, converting Tom Davies' low centre in style, before capping his hat-trick with a sublime shot from distance.
Ashley Williams added a fourth to put the gloss on Everton's biggest win of the season and send David Moyes back to the capital with his tail between his legs.
Here's what we learned from the Goodison Park clash.
1. Rooney shows worth on return to team
It takes a certain kind of player to thrive amid adversity. Times have been tough at Goodison Park, with manager Ronald Koeman sacked in October and temporary replacement David Unsworth failing for the most part to inspire a revival. Talk of relegation has even permeated onto the terraces, so Wednesday's game against fellow strugglers West Ham was seen as something of a six-pointer. Step forward Wayne Rooney.
Recalled to the team in a deeper role, the Croxteth-born star delivered his most complete performance of the season so far. Composed on the ball, a steady presence in defence and a threat in the final third, this was a captain's performance from Rooney.
Critics have argued that calls for the 32-year-old to play in a deeper role have been wide of the mark. Not on this evidence.
A smartly-taken first-half double was the first time Rooney has scored twice in a game since January 2016. That, though, was merely a teaser for what was to come. With his side under seize early in the second period, the former England captain's sublime first-time shot from inside his own half capped a magnificent individual display.
There is now an element of doubt as to where he actually fits into the Goodison Park picture. Allardyce and his staff surely cannot think of moving him from the withdrawn role against Huddersfield at the weekend.
Certainly, he did himself no harm in front of the soon-to-be-appointed manager.
There may be life in the old dog after all.
2. Moyes woes against former club continue
Heading into the crucial clash against his former team, much of the build-up unsurprisingly centred on David Moyes' terrible record when facing the Toffees. Indeed, the Scot has gone winless against the Blues since leaving Goodison Park.
From minute one, there was little chance of that changing here.
Facing the Premier League's worst defence statistically- and one missing its full first-choice backline- it will no doubt grieve the Glaswegian that his new charges failed to mount any substantial resistance in a torrid opening 45 minutes.
50-50s were lost meekly, possession regularly squandered, and most galling of all, the Hammers went a full half without registering a shot on target.
Matters did improve after the break, but given that this was an all-important relegation battle, the slow start reflects well on neither Moyes' ability to galvanise or his charges' willingness to scrap for points.
It was a night to forget for the former Everton manager on his return to Goodison. On this evidence, the Irons are in real trouble.
3. Pickford foils West Ham fightback to save Williams' bacon
It's been one of the quirks of Everton's season so far. With his goal peppered by all comers, Jordan Pickford has somehow still managed to be Everton's player of the campaign by a considerable distance.
Rarely afforded adequate protection by the likes of Williams and Jagielka, the ex-Sunderland stopper has often had to take matters into his own hands.
He did the same here. With the score at 2-0 and West Ham dominant, Williams' rash challenge on Diafra Sakho looked to have given the visitors a route back into the game. But a superb save denied Manuel Lanzini from the spot and shortly after Rooney made it 3-0.
On these moments, games turn.
Everton's £30m summer investment was money well spent.
4. One final hurrach for Unsworth as Allardyce waits in wings
On his last game at the helm, it was fitting that David Unsworth managed to get one final tune from his players.
Thrust into an incredibly difficult situation with an ailing squad, it seemed at times like Everton had done their former player a great disservice as matters went from back to worse on the pitch.
Tactical naivety and an overall lack of Premier League experience mean that the Lancastrian has not been considered for the permanent post, but he remains a popular figure both in the stands and on the pitch.
This, in many ways, was a typical Unsworth performance. Dogged and determined, with a bit of quality on top, Everton won battles all over the pitch against their beleaguered opponents.
Chants of "Rhino, Rhino" rang around Goodison on the final whistle by way of appreciation- and rightly so.
The irony is, has this display happened sooner, there may have been no need to appoint the relegation firefigher in Allardyce.
