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.
|Beating Bayern like this is ´madness´ - Tuchel|
|Moyes: Sunderland deserved something against Middlesbrough|
|Battle-scarred Arsenal star Sanchez takes to social media following last-gasp win|
|Sakho injury could bring end to Palace loan spell - Allardyce|
|Campbell expects extra ´spice´ in crucial north London derby|
|The target is clear - Wenger confident of Arsenal´s top four chances|
|The challenge is to keep going - Pochettino delighted as Spurs hunt Chelsea|
|If my grandmother had wheels, she´d be a bicycle - Luis Enrique won´t lean on Malaga in title race|
|Ancelotti feels Bayern only have themselves to blame for Dortmund defeat|
|Guardiola: If Man City miss out on Champions League we will adapt|
|He can play in 10 positions – Guardiola marvels over United star Pogba|
|Kane´s focus on Tottenham not Chelsea in title run-in|
|Deportivo La Coruna 2 Real Madrid 6: Six appeal gets Zidane´s men back on track|
|Chelsea continue FA Youth Cup dominance by thumping City|
|Paris Saint-Germain 5 Monaco 0: Emery´s men thrash youthful visitors|
|Alcacer honoured to play alongside ´unique´ Messi|
|Crystal Palace 0 Tottenham 1: Eriksen ensures Spurs remain in title hunt|
|Arsenal 1 Leicester City 0: Huth own goal keeps Arsenal in top four race|
|Bayern Munich 2 Borussia Dortmund 3: Dembele fires BVB into DFB-Pokal final|
|Middlesbrough 1 Sunderland 0: De Roon keeps faint survival hopes alive|
|Barcelona 7 Osasuna 1: Messi at the double to pile pressure on Madrid|
|Bauza hits out at AFA leadership: They know nothing about football|
|Infantino confirms use of VAR at 2018 World Cup|
|Van der Vaart tips Alli to become ´true great´|
|Ibrahimovic will fight to save career - Mourinho|
|Chelsea visited by HMRC officers as part of fraud investigation|
|Wenger admits Mbappe already out of Arsenal´s financial reach|
|AFC Champions League Review: Urawa batter Wanderers to reach last 16|
|Kongolo signs Feyenoord renewal|
|Xavi denies claiming Guardiola will move for Alli|
|Mourinho: Finishing above Guardiola means nothing|
|Silva doubtful for City but Aguero ready to face United in Manchester derby|
|Pogba ruled out of Manchester derby|
|Taylor gets two-game ban for Coleman challenge|
|Betting ban effectively forces me into retirement - Barton|
|Gignac: I´d die before I signed for PSG|
|Barton banned for 18 months over betting breaches|
|Messi only plays well for Barcelona - Romario|
|Bruno ordered to return to prison|
|David Moyes charged by FA over reporter ´slap´ comment|
|West Ham involved in HMRC probe into suspected tax fraud in football|
|Ronaldo out of Real Madrid clash with Deportivo|
|Champions League final in Monaco sights, says Glik|
|Vardy made right call in snubbing Arsenal - Shakespeare|
|James wants Real Madrid stay, says wife|
|Copa Libertadores Review: Iquique beat Zamora in seven-goal thriller|
|Pochettino hits back at ´enemy´ Xavi over Alli speculation|
|Mourinho: City favourites for top four, not United|
|Sanchez won´t be sold to Premier League rival, insists Arsenal boss Wenger|
|Simeone: Atletico have four finals after Villarreal loss|
|Goals are his life - Chelsea boss Conte delighted to see Costa back on target|
|Puel praises former pupil Hazard after Chelsea defeat|
|Carrasco suffers collarbone injury in Villarreal defeat|
|I have a squad of great men - Conte lauds Chelsea toughness in Southampton win|
|A massive step - Cahill, Hazard confident on Chelsea´s title charge|
|Borussia Monchengladbach 1 Eintracht Frankfurt 1 (aet, 6-7 pens): Hradecky and Hrgota heroes|
|Atletico Madrid 0 Villarreal 1: Late Soriano strike downs Simeone´s side|
|Wolves 0 Huddersfield Town 1: Brown seals play-off spot for Terriers|
|Angers 2 Guingamp 0: Letellier saves hosts from penalty injustice|
|Niasse red card overturned after Hull City appeal|
|Chelsea 4 Southampton 2: Hazard, Cahill and Costa move Conte´s men a step closer|
|Ramos receives one-match ban for Messi foul in El Clasico|
|AFC Champions League Review: Paulinho at the double in Guangzhou Evergrande rout|
|United need Griezmann - Silvestre backs proven goalscorer to emulate Rooney|
|Roma can achieve great things - Serie A club can join Europe´s elite, claims Monchi|
|Mourinho: Manchester derby not about me and Guardiola|
|Cavani extends PSG contract until 2020|
|Amsterdam ArenA to be renamed after Johan Cruyff|
|Surgery all that matters for Ibrahimovic - Mourinho realistic on United star´s future|
|Ibrahimovic should join me in MLS - Schweinsteiger|
|I cannot guarantee anything - Pochettino puts Alli future aside for Spurs title charge|
|Emery expecting full-strength Monaco for semi-final|
|Schweinsteiger has no regrets over Manchester United move|
|Sanchez a slow starter - Wenger|
|Zidane would not change Clasico approach|
|Sahin signs Dortmund contract extension|
|Luis Enrique wishes Barcelona had Madrid´s extra games|
|Ancelotti unhappy with Ribery performances|
|Rooney´s Manchester United future ´doesn´t look good´|
|Bale a doubt for Champions League semis with calf injury|
|Luis Enrique reiterates wish for Messi to end career at Barcelona|
|Tuchel relies on Reus to lead Dortmund past Bayern|
|Hazard not right for Chelsea captaincy|
|Pogba might regret leaving Juventus - Barzagli|
|Wenger in jovial mood over Arsenal future|
|Wenger dismisses Giroud to Marseille talk|
|Xavi expects Guardiola to make Alli move|
|Sanchez would be a good signing for Bayern – Matthaus|
|Hazard in no rush to sign Chelsea renewal amid ongoing Real Madrid links|
|Fernandez rules out Neymar exit, plays down Dybala talk|
|Herrera talks up Manchester derby importance|
|Maradona doubts Argentina World Cup qualification without Messi|
|Messi, Iniesta to renew deals soon – Fernandez|
|Benitez unsure over Newcastle future after promotion|
|Premier League win with Chelsea would be Conte´s greatest moment|
|Toure wants derby day tonic for faltering Manchester City|