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.
|Gallas expects Conte to revive Chelsea|
|Deschamps ´annoyed, but not worried´ by Varane´s absence|
|´Impossible´ to see MSN leaving Barcelona - Bartomeu|
|Thiago pledges future to Bayern|
|AFC Champions League Review: Urawa pay the penalty as Seoul advance|
|Uruguay v Trinidad and Tobago: Sanchez skips final to help Suarez-less La Celeste|
|Benitez ´convinced´ he can win trophies at Newcastle|
|Nigeria v Mali: Moses among many absentees for Super Eagles|
|Benitez to stay at Newcastle|
|Kramaric leaves Leicester for Hoffenheim permanently|
|Neustadter gets green light for Russia Euro 2016 selection|
|Chile v Jamaica: Copa plans crystallize in Vina del Mar|
|Ledley making progress in bid to prove Euro 2016 fitness|
|Gotze returns to Germany training|
|Ronaldo: Madrid would be smart to give me a new deal|
|Varane disappointed by Euros absence|
|Republic of Ireland v Netherlands: O´Neill wants confident display|
|Ronaldo shakes off injury in Real Madrid training|
|Atletico star Griezmann ´listening to different clubs´|
|United States - Ecuador Preview: Klinsmann pins hopes on Yedlin as Copa preparations continue|
|Gold tells Middlesbrough to ´dream on´ over Antonio|
|Schweinsteiger wants Mourinho to spice up Manchester derby|
|England v Australia: All eyes on Rashford debut|
|Aggressive Premier League better for me - Xhaka|
|Schweinsteiger ´right on schedule´ for Euro 2016|
|Darmian relishing Euros after return from injury|
|Northern Ireland v Belarus: Last chance to impress as O´Neill prepares to trim squad|
|Ventura leaves Torino amid Italy talk, Mihajlovic appointed|
|Sevilla confident of keeping Emery|
|Godin wants Atletico to use 2014 defeat as inspiration|
|Xhaka agrees Arsenal move|
|Idolisation of Ibrahimovic warranted Sweden captaincy - Hamren|
|Scholes hopes Mourinho keeps Giggs at Manchester United|
|Gotze snubbing Liverpool will boost Germany - Bierhoff|
|Bosz honoured by Ajax appointment|
|Ramos highlights Griezmann threat|
|Record-chasing Ronaldo and taming the Wolves - Real Madrid´s route to the Champions League final|
|Donnarumma dreams of being Milan captain|
|Koke: History, not revenge motivating Atletico|
|Costa Rica v Venezuela: Hosts ramp up preparations for maiden Copa America tilt|
|Argentina v Honduras: Messi and co warm up for Copa America|
|USA will win a World Cup, says Donovan|
|Pumas UNAM 2 Independiente del Valle 1 (3-3 agg, 3-5 on penalties): Hosts suffer shoot-out heartbrea|
|Gracia leaves Malaga as Rubin Kazan loom|
|Messi: Argentina deserve to be Copa America champions|
|Dybala included in Argentina´s preliminary Olympics squad|
|Mourinho and United a ´good wedding´ - Ancelotti|
|Klinsmann: Copa America better than Euros|
|Messi: Joining Barcelona not an easy decision|
|Carrico receives four-game ban for homophobic slur|
|Dani Alves wants Atletico to win Champions League|
|McNair out to impress ´world-class´ Mourinho|
|Ranieri: Premier League survival is Leicester´s priority next season|
|Argentina forward Lavezzi suffers hamstring scare|
|Koeman talks ´very positive´, say Southampton|
|Rami replaces injured Varane in France´s Euro 2016 squad|
|Matthaus applauds Gotze for rejecting ´easy solution´ of Liverpool|
|Suarez silenced his doubters - De Boer|
|AFC Champions League Review: Jeonbuk, Shanghai SIPG progress|
|Klopp can take Liverpool right to the top, says McAllister|
|Lindelof happy at Benfica amid Real Madrid, Barcelona links|
|Zidane is perfect on and off the pitch - Lippi|
|Bale: Zidane has brought the best out of Real Madrid|
|Favre takes over as Puel and Nice part ways|
|Liverpool complete Karius deal|
|Van Gaal was treated poorly by United, but Mourinho will be a success - De Boer|
|Dani Alves: I have won more titles than Pele|
|I know who I´m taking - Conte sure on Euro 2016 selection|
|Xavi backs Guardiola to ´change the face of English football´|
|Lucescu appointed Zenit boss|
|Manchester United and Liverpool hit with €40,000 fines|
|Weinzierl: I have nothing to lose at Schalke|
|Rangers complete Barton signing|
|Italy better placed as underdogs ahead of Euro´s - Motta|
|Cantona: I love Mourinho, but he is not Manchester United|
|Ben Arfa wants Lyon move - Aulas|
|David Silva praises Iniesta´s Copa del Rey heroics|
|´It was a little scare´ - Ronaldo plays down injury fears|
|Eder the real deal for Lille|
|Van Gaal treated unfairly during Manchester United spell - Daley Blind|
|Ginola doing ´very well´ after heart surgery|
|Depay rules out Manchester United exit following Van Gaal departure|
|Hojbjerg confirms desire to leave Bayern|
|Ronaldo leaves Madrid training early after knock|
|Abbiati unimpressed with Milan players´ attitude|
|Pepe calls on Madrid to continue making history|
|Ayestaran signs two-year deal with Valencia|
|Montolivo, Antonelli sign new AC Milan contracts|
|Ronaldo ready for UCL final after being rested from practice match|
|Hummels, Sanches deals will not stop Bayern spending - Rummenigge|
|Oblak´s penalty heroics, Griezmann´s Barcelona brace - Atletico Madrid´s route to the Champions Leag|
|Salvio all but confirms Gaitan will join Atletico Madrid|
|Motta warns PSG over Ronaldo, Neymar interest|
|Europa League Mourinho´s best hope for United trophy - Sheringham|
|Injustice if Iniesta never wins a Ballon d´Or - Del Bosque|
|Van Gaal didn´t deserve United sacking - Blind|
|I´ll be happy if we make Euro 2016 semi-finals - Del Bosque|
|Koke: Why would I want to leave Atletico?|
|Fofana could retire aged 25 - Lyon president|
|Sandro set to leave Barcelona|
|Silva plays down injury worries ahead of Euro 2016|
|United would be brave to appoint Mourinho, says Schmeichel|
|Neymar adamant he is happy at Barcelona|
|Wilshere: Arsenal play me out of position|
|Ryan backs former coach Neville|
|Keane talks up Galaxy move for Ronaldo|
|´Free agent´ Diarra wants Mourinho reunion|