Tomas Pina's fortuitous second-half goal saw favourites Napoli crash out of the Europa League after a 1-1 draw against Villarreal.
The visitors were handily placed going into the second leg with a 1-0 lead, but Marek Hamsik's long-range effort made it all-square at the break.
Napoli had been by far the most adventurous side in the first period, but their dominance counted for little as Pina equalised shortly before the hour mark to claim a crucial away goal for the Yellow Submarine to see them through to the last 16.
A loose corner from Denis Suarez, who had scored the only goal in the first leg, found its way to Pina outside the area and the midfielder hit a hopeful ball into the area, only to see his overhit cross loop over Pepe Reina and into the top corner.
Napoli, who are now without a win in four games, only had themselves to blame after spurning a host of first-half chances.
Gonzalo Higuain's mini-drought in front of goal continued on a frustrating night for the striker, but he could have given his side a dream start in the opening minutes when his left-footed effort found the side netting after he was played in down the channel.
Cedric Bakambu raced clear at the other end but could only hit a weak shot straight at Reina, who got down well to save a low shot and parry it away.
That was as close as Villarreal got in the opening period, as Napoli asked persistent questions of their opponents, with Dries Mertens particularly prominent.
However it was Hamsik who opened the scoring on the night, latching onto a knock-down before striking a clean volley beyond Alphonse Areola and into the bottom corner for his third of the competition.
Belgian winger Mertens caused problems down the left throughout, but his finishing was off as he drove weakly at Areola.
Higuain smashed a volley over the bar shortly after as Villarreal were forced onto the back foot for much of the first half.
The game turned scrappy as the break approached, but Vlad Chiriches headed wastefully wide and Mertens saw a shot deflected onto his own post by Mateo Musacchio.
Villarreal were grateful for the whistle, and they used the break to good effect as they came out revitalised for the second period.
Napoli's rhythm deserted them in the second half as gradually the visitors began to press higher up the pitch and put Gli Azzurri under pressure.
Reina reacted well to prevent Bakambu from tapping in after getting down well to smother Antonio Rukavina's pull-back, but they did not have to wait much longer.
Pina gave his side a vital away goal from the resulting corner to leave Napoli needing two to stay in the competition but the visiting defence dropped deeper and deeper as they sought to protect their lead.
Mertens and Lorenzo Insigne forced good saves from Areola but Napoli became frustrated and their finishing became more erratic as they slipped towards a damaging loss.