Nottingham Forest secured a famous win as Taiwo Awoniyi scored the only goal to beat West Ham as Premier League football returned to the City Ground after a 23-year absence.
Awoniyi, Forest's £17m record signing this summer, applied the first-time finish after Jesse Lingard's effort had been deflected into his path off Hammers defender Ben Johnson.
Goalkeeper Dean Henderson was Forest's other hero, denying Declan Rice with a second-half penalty save.
The Hammers could also reflect on two strikes from distance that hit the crossbar and another excellent Henderson save from Tomas Soucek as they started the season with successive defeats.
However, for Forest and their boss Steve Cooper, it was another unforgettable day for a club who were bottom of the Championship less than 12 months ago.
Spurred on by a frenzied home crowd, Forest started on the front foot and had enough to keep West Ham at bay even after their energetic early efforts started to slow.
A famous Forest win
If there was an element of Forest not quite being ready for their top-flight return, given negotiations around a new kit sponsor are still to reach a conclusion and the most recent of their 14 summer signings - £20m forward Emmanuel Dennis and free-transfer arrival Cheikhou Kouyate - were not available, the same was not true of their fans.
For hours before kick-off, they thronged the streets around the City Ground and the noise they made when the home players emerged for their warm-up was only a foretaste of the spine-tingling reception when they emerged from the tunnel for real.
Forest responded by tearing into their opponents at a furious pace. Moussa Niakhate and Awoniyi both threatened with headers, while Neco Williams drew a decent save from Lukasz Fabianski, who also had to palm away a goal-bound header from team-mate Soucek.
The backing kept Forest going on a blisteringly hot day - and the reward came in first-half stoppage time.
Awoniyi spent six years as a Liverpool player without making a single first-team appearance, before moving to Union Berlin in 2021 and then, a year later, to Forest.
As with a number of the club's summer recruits, Awoniyi has a point to prove. His finish was reactive, but he needed to be in the right place at the right time - and his name will now go into Forest folklore along with all the other great names associated with the two-time European Cup winners.
Henderson is another who wants to show how good he is. The on-loan Manchester United man produced a superb save at the start of the second half when Soucek was first to the loose ball after Pablo Fornals' strike bounced off the bar.Declan Rice has now missed two of the three penalties he has taken in the Premier League
His best moment was still to come though. With England coach Gareth Southgate watching on from the directors' box and coming 24 hours after United keeper David de Gea's nightmare at Brentford, it could not have come on a better day as he went to his right to repel Rice's spot-kick after Scott McKenna's handball.
Forest thought they had a second through Brennan Johnson but it was ruled out for offside after a VAR intervention.
It didn't matter in the end, although there was one negative in the injury centre-back Niakhate picked up before the end.
West Ham fail awkward test
This would have been an awkward assignment for West Ham anyway given the atmosphere they were bound to encounter.
But they hardly helped themselves.
With penalty expert Mark Noble retiring, Rice has taken that responsibility as well as the captain's armband.
However, his spot-kick was poor and lacked the accuracy to take it beyond Henderson's reach.
Rice had earlier set Said Benrahma up with a superb defence-splitting pass, only for the goal to be ruled out because Michail Antonio - given a standing ovation from the home fans when he was substituted in recognition of the season he spent as a Forest player - had barged over Orel Mangala in the build-up.
Benrahma also hit the bar with another superb effort, with Soucek denied a tap-in as Harry Toffolo made a dramatic clearance on the line.
With £30.5m striker Gianluca Scamacca unable to make an impact after replacing Antonio, West Ham find themselves without a point after two games and plenty of work ahead of them if they are to match the last two seasons' top-seven finishes.
Player of the match
N WilliamsNeco Williams
Squad number7Player nameN Williams
Squad number1Player nameHenderson
Squad number9Player nameAwoniyi
Squad number14Player nameO'Brien
Squad number15Player nameToffolo
Squad number26Player nameMcKenna
Squad number20Player nameJohnson
Squad number19Player nameNiakhaté
Squad number5Player nameMangala
Squad number4Player nameWorrall
Squad number3Player nameS Cook
Squad number16Player nameSurridge
Squad number11Player nameLingard
Squad number18Player nameCafú
West Ham United
Squad number22Player nameBenrahma
Squad number1Player nameFabianski
Squad number8Player nameFornals
Squad number3Player nameCresswell
Squad number28Player nameSoucek
Squad number9Player nameAntonio
Squad number5Player nameCoufal
Squad number20Player nameBowen
Squad number2Player nameJohnson
Squad number7Player nameScamacca
Squad number10Player nameLanzini
Squad number14Player nameCornet
Squad number4Player nameZouma
Squad number41Player nameRice
20Johnson9Awoniyi1HendersonBooked at 75mins4Worrall19NiakhatéSubstituted forS Cookat 79'minutes26McKennaBooked at 64mins7N Williams5MangalaSubstituted forRibeiro Diasat 84'minutes14O'Brien15Toffolo11Lingard20JohnsonBooked at 90mins9AwoniyiSubstituted forSurridgeat 72'minutesBooked at 90mins
Substitutes2Biancone3S Cook6Mbe Soh13Hennessey16Surridge17Mighten18Ribeiro Dias33Taylor41Hammond
9Antonio1Fabianski5Coufal4Zouma2Johnson3Cresswell28Soucek41RiceBooked at 9mins20BowenSubstituted forCornetat 85'minutes22Benrahma8FornalsSubstituted forLanziniat 69'minutes9AntonioSubstituted forScamaccaat 69'minutes
Match ends, Nottingham Forest 1, West Ham United 0.
Second Half ends, Nottingham Forest 1, West Ham United 0.
Sam Surridge (Nottingham Forest) is shown the yellow card.
Brennan Johnson (Nottingham Forest) is shown the yellow card.
Foul by Vladimír Coufal (West Ham United).
Sam Surridge (Nottingham Forest) wins a free kick in the attacking half.
Attempt missed. Tomás Soucek (West Ham United) right footed shot from the centre of the box is high and wide to the left. Assisted by Aaron Cresswell with a cross following a corner.
Corner, West Ham United. Conceded by Joe Worrall.
Attempt blocked. Manuel Lanzini (West Ham United) right footed shot from outside the box is blocked. Assisted by Saïd Benrahma.
Substitution, West Ham United. Maxwel Cornet replaces Jarrod Bowen.
Substitution, Nottingham Forest. Cafú replaces Orel Mangala.
Foul by Gianluca Scamacca (West Ham United).
Joe Worrall (Nottingham Forest) wins a free kick in the defensive half.
Corner, West Ham United. Conceded by Steve Cook.
Attempt blocked. Kurt Zouma (West Ham United) header from the centre of the box is blocked. Assisted by Aaron Cresswell with a cross.
Corner, West Ham United. Conceded by Neco Williams.
Corner, Nottingham Forest. Conceded by Ben Johnson.
Substitution, Nottingham Forest. Steve Cook replaces Moussa Niakhaté because of an injury.
Attempt blocked. Gianluca Scamacca (West Ham United) right footed shot from the left side of the box is blocked. Assisted by Aaron Cresswell.
Dean Henderson (Nottingham Forest) is shown the yellow card.Our coverage of your Premier League club is bigger and better than ever before - here's everything you need to know to make sure you never miss a moment