West Ham United reached their first major European final since 1976 after they overcame AZ Alkmaar in their Europa Conference League semi-final.
David Moyes' side soaked up plenty of pressure at AFAS Stadium until Pablo Fornals scored on the counter-attack in second-half injury time.
The night, however, was soured by unpleasant scenes off the pitch.
AZ Alkmaar fans attacked an area in which friends and family of the West Ham players were watching the match.
West Ham will face Fiorentina, who beat Basel in extra time in the other semi-final.
The Hammers are hoping to lift their first major trophy since they lifted the 1980 FA Cup; they were one of three winners of the 1999 Intertoto Cup.
Hammers end 47-year wait for final
West Ham's last European final had been in the 1975-76 Cup Winners' Cup when they lost 4-2 to Anderlecht.
They came agonisingly close to breaking that duck last season, losing 3-1 on aggregate to eventual winners Eintracht Frankfurt in the Europa League semi-finals.
This time around they were disciplined, keeping their hosts at arm's length for much of their second leg.
Paqueta clipped the outside of the post in the 26th minute after good work from Michail Antonio, while captain Declan Rice forced a good save from AZ keeper Mat Ryan shortly after the restart.
Defender Nayef Aguerd also dragged an effort wide from close range in the 82nd minute, before Pablo Fornals raced clear in injury time and buried the ball into the bottom corner to seal the tie.
It means the Hammers have an opportunity to win a first European trophy since they lifted the Cup Winners' Cup in 1965.
West Ham boss David Moyes has never won a major trophy as a managerIt would cap off a fine turnaround for Moyes' side, who were booed by their own fans on 5 April when they suffered a 5-1 home defeat by Newcastle to leave them just a point clear of the Premier League relegation zone.
The Hammers are 15th in the table with two games left, and need just a point across their final two league games to mathematically confirm their safety.
AZ second-best against mighty West Ham
Eredivisie side AZ were in their first European semi-final since losing to Sporting Lisbon in the last four of the 2004-05 Uefa Cup.
The 1981 Uefa Cup finalists had enjoyed an impressive European run, beating Lazio in the last 16 and coming from two goals down to beat Anderlecht on penalties in the quarter-finals.
They threw everything at West Ham in the closing stages - and Hammers defender Thilo Kehrer nearly caught out keeper Alphonse Areola with a risky back-pass.
And defender Kurt Zouma was relieved not to have been penalised for a handball in the area, with the video assistant referee deciding not to overturn Slovakian referee Ivan Kruzliak's non-penalty call.
Despite opening the scoring in London last week, AZ slumped to a 3-1 aggregate defeat. They need one more point from their final two league fixtures to secure a top-four finish and qualify for next season's Europa Conference League qualifiers.
Player of the match
FornalsPablo Fornals
AZ Alkmaar
Squad number1Player nameRyan
Squad number31Player nameBeukema
Squad number16Player nameMijnans
Squad number5Player nameKerkez
Squad number11Player nameKarlsson
Squad number8Player nameClasie
Squad number2Player nameSugawara
Squad number3Player nameHatzidiakos
Squad number9Player namePavlidis
Squad number6Player nameReijnders
Squad number35Player nameMeerdink
Squad number19Player namevan Brederode
Squad number34Player namede Wit
Squad number10Player namede Wit
Squad number23Player nameLahdo
West Ham United
Squad number8Player nameFornals
Squad number11Player nameLucas Paquetá
Squad number41Player nameRice
Squad number27Player nameAguerd
Squad number9Player nameAntonio
Squad number4Player nameZouma
Squad number13Player nameAréola
Squad number24Player nameKehrer
Squad number18Player nameIngs
Squad number22Player nameBenrahma
Squad number28Player nameSoucek
Squad number3Player nameCresswell
Squad number20Player nameBowen
Squad number12Player nameDownes
Line-ups
AZ Alkmaar
Formation 4-3-3
1Ryan
2Sugawara31Beukema3Hatzidiakos5Kerkez
16Mijnans8Clasie6Reijnders
19van Brederode9Pavlidis11Karlsson
1Ryan2Sugawara31Beukema3Hatzidiakos5KerkezSubstituted forde Witat 85'minutes16MijnansSubstituted forde Witat 70'minutes8Clasie6Reijnders19van BrederodeSubstituted forLahdoat 78'minutes9Pavlidis11KarlssonSubstituted forMeerdinkat 85'minutesSubstitutes
10de Wit12Verhulst14Mihailovic23Lahdo25Bazoer27Vanheusden28Buurmeester34de Wit35Meerdink46Goes54DeenWest Ham
Formation 4-3-3
13Aréola
24Kehrer4Zouma27Aguerd3Cresswell
28Soucek41Rice11Lucas Paquetá
20Bowen9Antonio22Benrahma
13Aréola24KehrerBooked at 64mins4Zouma27Aguerd3Cresswell28SoucekBooked at 60mins41Rice11Lucas PaquetáSubstituted forDownesat 90+5'minutes20Bowen9AntonioSubstituted forIngsat 85'minutes22BenrahmaSubstituted forFornalsat 75'minutesSubstitutes
1Fabianski2Johnson5Coufal8Fornals10Lanzini12Downes14Cornet18Ings21Ogbonna33Emerson49Anang72MubamaLive Text
Match ends, AZ 0, West Ham United 1.
Second Half ends, AZ 0, West Ham United 1.
Foul by Sam Beukema (AZ).
Kurt Zouma (West Ham United) wins a free kick in the defensive half.
Substitution, West Ham United. Flynn Downes replaces Lucas Paquetá.
Goal! AZ 0, West Ham United 1. Pablo Fornals (West Ham United) right footed shot from outside the box to the bottom left corner following a fast break.
Delay over. They are ready to continue.
Delay in match because of an injury Alphonse Aréola (West Ham United).
Foul by Mexx Meerdink (AZ).
Alphonse Aréola (West Ham United) wins a free kick in the defensive half.
Substitution, AZ. Mexx Meerdink replaces Jesper Karlsson.
Substitution, West Ham United. Danny Ings replaces Michail Antonio.
Substitution, AZ. Mees de Wit replaces Milos Kerkez.
Hand ball by Jesper Karlsson (AZ).
Attempt missed. Nayef Aguerd (West Ham United) left footed shot from the centre of the box misses to the right. Assisted by Tomás Soucek.
Attempt missed. Tomás Soucek (West Ham United) right footed shot from the centre of the box misses to the right. Assisted by Michail Antonio.
Corner, West Ham United. Conceded by Sam Beukema.
Foul by Vangelis Pavlidis (AZ).
Thilo Kehrer (West Ham United) wins a free kick in the defensive half.
Yukinari Sugawara (AZ) wins a free kick in the defensive half.