Giuseppe Rossi scored the winner as Villarreal rallied to beat Napoli 2-1 to reach the last 16 of the Europa League on Thursday.
After a scoreless first leg in Italy, Napoli was ahead after 22 minutes when Marek Hamsik headed Ezequiel Lavezzi's cross underneath goalkeeper Diego Lopez. Napoli fans fell on to the field as a barrier collapsed in the ensuing celebration at El Madrigal Stadium. Despite fans showering down onto the side of the field, only a few were taken away with slight injuries.
Borja Valero set up both of Villarreal's scores as he threaded a pass deep into the right side of the area to Nilmar to equalize in the 43rd. He then fed Rossi for the winner in the second minute of first-half added time.
Italy striker Rossi scored his sixth of the competition after his shot deflected off Juan Camilo Zuniga to loop in over goalkeeper Morgan de Sanctis.
Villarreal will now face Bundesliga side Bayer Leverkusen, which beat Metalist 2-0 to advance 6-0 on aggregate.
Lavezzi led Napoli's attack as coach Walter Mazzarri started several regulars - including Edinson Cavani - on the substitutes bench with a match against Serie A leader AC Milan looming and Lavezzi unavailable for domestic play due to a spitting ban.
The Argentine striker twice went close before Hamsik's opener as the Italian side controlled the first half hour against a tense Villarreal team that couldn't seem to string its attack together inside Napoli's half.
Lopez denied Lavezzi again before Villarreal finally begun to find space against a physical Napoli side.
Borja - who had two hard shots fly wide early - was the catalyst to Villarreal's attack as he found Nilmar for his first goal since December.
With the Napoli retreating into a more defensive game, Nilmar then stole away at the half with Borja picking up the loose ball to find Rossi, whose shot deflected off Zuniga into goal for the Italy striker's 21st goal in all competitions.
After Santi Cazorla sent a good chance high, Mazzarri brought on Cavani for Jose Ernesto Sosa in the 53rd and the Uruguayan was the Italian side's clearest threat towards the end as he guided a header just wide then volleyed off the far post in the 66th. Lavezzi found the near post in the 77th.
Cavani volleyed over goal late but Napoli couldn't score the second that would have taken the 1989 UEFA Cup champions through.
It was Napoli's first defeat to a Spanish side in five matches, dating to a 2-0 loss to Real Madrid during the 1987-88 season.
