Gonzalo Higuain and Gokhan Inler denied Swansea City a place in the last 16 of the UEFA Europa League as Napoli progressed 3-1 on Thursday.
With Rafael Benitez's side strongly tipped as one of the tournament's favourites, many expected the Serie A outfit to progress following a 0-0 draw in Wales last week in the first leg of the last-32 tie.
But for almost 50 minutes at the Stadio San Paolo it looked as if Jonathan de Guzman's goal would see Swansea through via the away goals rule after Lorenzo Insigne had earlier put Napoli ahead.
Insigne latched onto Higuain's headed flick in the 17th minute and lobbed a deft finish over the advancing Michel Vorm, but Swansea responded strongly and were level 13 minutes later.
A glorious team move eventually found De Guzman in space and the Dutchman fired a left-footed strike beyond Pepe Reina to put his side in the ascendancy.
The visitors looked assured for much of the game, but Swansea's hopes were dashed 12 minutes from time when an unfortunate ricochet off Ben Davies fell kindly for Higuain, who smashed the ball beyond a helpless Vorm.
Inler rubbed salt into the wound in the final minute of stoppage time, coolly slotting beyond Vorm as Swansea left themselves exposed in chasing a second equaliser.
Victory means Benitez, who won the tournament last year while in charge of Chelsea, remains on course to defend his title.
Marvin Emnes, one of three Swansea changes to the starting XI from the home leg, had the first sight of goal in the 11th minute, but, after being played in by Pablo Hernandez, the Dutchman saw his chipped effort over Reina cleared from just in front of the goalline by Raul Albiol.
The hosts ought to have broken the deadlock themselves four minutes later, but Higuain blazed over from 10 yards after linking up with Goran Pandev.
Swansea failed to heed the warning in the 17th minute, Insigne springing the offside trap before lofting his finish over Vorm and into the net.
The Swansea defence was in disarray, Higuain flashing an effort a yard wide with the visitors apparently still reeling from falling behind.
The Premier League side recovered their composure, however, and were level on the half-hour mark.
A slick passing move resulted in the ball being fed into Wilfried Bony and his clever flick was picked up by De Guzman, who fired left footed beyond Reina to provoke jeers from the home crowd.
The goal gave Swansea added confidence and they enjoyed long spells of possession, Bony cutting inside Henrique before testing Reina as the half drew to a close.
Midway through the second half, Insigne broke through only to see his effort blocked by Chico Flores, before Bony wasted a glorious chance when he headed Hernandez's cross straight into the arms of Reina.
Swansea hearts were broken on 78 minutes when the ball bounced off both Flores and Davies and landed perfectly for Higuain, who made no mistake from 10 yards.
With almost the last kick of the game and with Swansea completely exposed, substitute Marek Hamsik fed Inler, who beat Vorm to seal the win and set up a tie with Porto in the next round.
|Pellegrini: Sterling will justify price tag|
|Cavani hit with two-match Uruguay ban|
|Bonucci to remain at Juve until 2020|
|No bids for Berahino - West Brom|
|Putin: Blatter deserves a Nobel prize|
|Howe: Swansea a benchmark for Bournemouth|
|New Parma to play in Serie D|
|Mata vows to hit the goal trail at United|
|Drogba ´perfect fit´ for Montreal|
|Berahino ´not yet´ ready for Tottenham - Irvine|
|Romero lauds caring Van Gaal|
|Jese flying at Real under Rafa|
|Sampdoria unwilling to pay €10m for Balotelli|
|Mourinho talks up Arsenal title chances|
|Hull sign Ryan Taylor, Sam Clucas|
|Kane, Pochettino hail MLS All-Star test|
|Di Santo sorry for swift Werder departure|
|Mourinho tells Ronaldo: Team honours come first|
|Khedira returns to Juve training|
|Celtic v Qarabag: Champions League return of utmost importance, says Collins|
|Pellegrini: Jovetic had to go|
|Manquillo completes Marseille move|
|Schalke reject Juve´s Draxler bid|
|Blanc: Di Maria deal ´close´|
|Di Santo debut ends in stalemate|
|Fire sign Drogba, trade him to Montreal Impact|
|FIFA and UEFA welcome ruling on third-party ownership|
|Juve kick off title defence against Udinese|
|Stoke sign free agent Afellay|
|Benitez confident Ramos will stay|
|Fenerbahce issue warning to fans|
|UEFA Champions League Preview: De Boer confident Ajax are ready for Vienna test|
|Bility: I am the favourite for FIFA presidency|
|Pienaar to miss start of season|
|Vietnam 1 Manchester City 8: Sterling shines as tourists run riot|
|All-Star Keane relishing Spurs clash|
|Shaun Wright-Phillips joins brother Bradley at Red Bulls|
|Inter 0 Real Madrid 3: Rodriguez stunner caps comfortable win|
|Villa sign Ayew|
|Watford complete Berghuis transfer|
|Robben returns to Bayern training|
|Pulis anxious to make West Brom additions|
|David Luiz eager to welcome ´fantastic´ Di Maria|
|Fernando injury free ahead of new campaign|
|Hummels blames weight issues for poor season|
|Defoe hoping for early Sunderland goals|
|Depay hints at identity of ´surprise´ United striker|
|Tigres UANL v River Plate: Hosts look to bounce back and make history|
|Crespo set for Villa move|
|Terry: I would never join a Premier League rival|
|Van Gaal coy on United future|
|Romero to cover potential De Gea exit - Van Gaal|
|Uruguay win men´s football gold at Pan Am Games|
|Pirlo thanks New York City fans for ´beautiful´ welcome|
|Mexico capitalised on ´the mistakes we made´ - Schafer|
|Herrera delighted with Mexico display|
|MLS Review: Whitecaps build happy home, Pirlo debuts|
|Guardado wins Golden Ball at Gold Cup|
|NZF confirms Olympics disqualification appeal|
|Jamaica 1 Mexico 3: CONCACAF giants complete form turnaround|
|New York Red Bulls 2 Benfica 1: Another scalp for MLS side|
|Romero signs with United|
|Moghreb Tetouan 1 Al Hilal Omdurman 1: Visitors go top|
|Van Gaal rules out Ronaldo bid|
|Pique open to Barca captaincy|
|Pirlo makes MLS bow in thrilling NYC victory|
|Coutinho and Can return for Liverpool U21s|
|Walcott deal ´closer´, says Wenger|
|Arsenal 1 Wolfsburg 0: Walcott the match-winner in Emirates Cup finale|
|Di Santo links up with Schalke squad|
|Lukaku treble sinks Hearts|
|Benitez again refutes Ronaldo rift rumours|
|Pepe sure Ramos will stay at Real|
|City target De Bruyne named Germany´s Player of the Year|
|Montero spoils McCarthy´s Palace debut|
|Lyon 0 Villarreal 2: Soriano, Baptistao seal comfortable win in Emirates Cup|
|Wijnaldum on target as Newcastle are held|
|Mourinho: Rivals trying to buy the title|
|Jovetic set for Inter medical|
|RFS in ´denial´ over racism issue, claims Football Against Racism in Europe|
|Salah not staying at Chelsea - Mourinho|
|Mbemba closes in on Newcastle switch|
|Ibrahimovic: Di Maria will take PSG to another level|
|Delph: Don´t compare me to Pogba|
|Dundee United sign Sneijder|
|Morata relishing new-look Juve strikeforce|
|Strachan "not scared" of England after World Cup qualifying draw|
|Brazil claim football, basketball, handball gold in Toronto|
|Lampard´s debut delayed again, Pirlo ready to play|
|Mourinho open to Premier League matches in US|
|MLS Review: Texas unites to hurt Galaxy|
|Luis Enrique: United can emulate Barca revival|
|Van Gaal singles out Januzaj, hails United´s forwards|
|Blanc still hopeful PSG will sign Di Maria|
|Irish international Cunningham seeks Bristol City exit|
|Italy embracing Spain challenge in World Cup qualifying|
|Dos Santos brothers in doubt for Gold Cup final|
|PSG 1 Chelsea 1 (aet, 5-6 on penalties): Courtois clinches victory for Mourinho´s men|
|United States 1 Panama 1 (aet, 2-3 on penalties): Mejia denies hosts third|
|ES Setif 1 Al Merreikh 1: Sudanese deny title-holders at home|
|CONCACAF admit referee errors in Gold Cup semi-final|
|Dutch favourites in Group A - Deschamps|
|Barcelona 1 Manchester United 3: Rooney, Lingard and Januzaj maintain winning start|