Napoli fell to a surprise defeat at home to Atalanta, as Duvan Zapata and Mario Pasalic scored to overturn Dries Mertens' opener and move their side into fifth place.
The home side started the brighter of the two, with the potent strike-force of Dries Mertens and Arkadiusz Milik - with 28 goals between them in Serie A prior to kick-off - looking too much for La Dea to handle.
The former was particularly lively, and after sparing Andrea Masiello's blushes by losing his footing after the defender misjudged the bounce of the ball and let him through, he got on the end of a Kevin Malcuit cross to poke his side into the lead just before the half hour mark.
Pierluigi Gollini had to be on his toes on a number of occasions, and did well to deny Piotr Zielinski with some excellent one-on-one goalkeeping, while Arkadiusz Milik did get the ball past the keeper early in the second half, only for Masiello to recover it with a superb last-ditch clearance.
Napoli continued to dominate into the second half, but their profligacy in front of goal came back to bite them, and it was Zupata's performance that would prove decisive. The former Napoli man forced his 26th goal of the season over the line to level things up with 20 minutes remaining, and then laid off Chelsea loanee Pasalic for what would prove to be the winner ten minutes later.
Key Talking Point
With Inter and Roma playing out a draw and Milan dropping points this weekend, the opportunity was there for Napoli to bounce back from Europa League defeat and cement their grip on second place, and although they found themselves without Vlad Chiriches after he was forced off with another injury on 13 minutes, they initially looked set to do so.
They made four changes to the side who were so disappointing during the week, with David Ospina returning in goals, while Kevin Malcuit and Elseid Hysaj replaced Nikola Maksimovic and Faouzi Ghoulam in the full-back positions, and Lorenzo Insigne made way for Milik to start up front.
The result was a rejuvenated, energetic first half performance, and they were unlucky only to be 1-0 up at half time following Mertens' 15th of the season, but kept up their dominance well into the second 45.
Mertens would go on to spurn a catalogue of chances as the second goal looked certain to come, but it just wouldn't go in, and they were punished when Duvan Zapata - a Napoli player until the summer - squeezed in his 26th of the season.
From there, the home side collapsed, and things went from bad to worse when Pasalic picked up Zapata's pass to score the winner. Napoli still look assured of second place, but their second defeat at home in the league was a tough one to take.
Starting XI: Ospina (6); Malcuit (6), Chiriches (5), Koulibaly (6), Hysaj (6); Callejon (6), Allan (6), Fabian (6), Zielinski (6); Mertens* (8), Milik (7)
Substitutes: Luperto (6), Younes (5), Verdi (5)
Star Man: Dries Mertens
The Belgian, as ever, was at the heart of everything, and after a difficult couple of games against Arsenal, he was back at his best. He's enjoyed another formidable season, and his pace and creativity - as well as his natural goalscoring ability - could easily have been the difference yet again for his side.
Incidentally, his first half strike - his 105th for Napoli - took him past Edinson Cavani as the club's third top goalscorer of all time.
The one criticism of his game was his end product. He had enough chances to win three matches as his side dominated - once opting to square it to an unsuspecting Milik when it looked impossible to miss himself - and had he taken them, his side would have won easily.
He found himself subbed for Amin Younes with 15 minutes left at 1-1, but his movement would have been too much for any defence, and he was absolutely key to everything his side did going forward.
Starting XI: Gollini (7); Mancini (6), Djimsiti (6), Masiello (5); Hateboer (6), De Roon (6), Pasalic (7), Freuler (5), Castagne (6); Gomez (7), Zupata (7)
Substitutes: Palomino (6), Ilicic (7), Gosens (5)
Napoli will look to see out second place when they visit Frosinone next Sunday, and play host to Cagliari back at Stadio San Paolo exactly a week later.
Atalanta, meanwhile, have the visit of Fiorentina to look forward to in Thursday, and have another home game on Monday when Udinese come to town.