Napoli’s defence was disastrous as they crumbled to a 3-0 Europa League defeat against PSV in Eindhoven.
The Partenopei flattened AIK 4-0 in their first Group F game and again rotated the squad with youngsters like Lorenzo Insigne, Edu Vargas and Omar El Kaddouri, but Marek Hamsik was suspended. PSV could count on the experience of ex-Milan midfielder Mark Van Bommel, plus rising stars like Kevin Strootman and Ola Toivonen.
It was a poor start from El Kaddouri, who got booked after 120 seconds for a clumsy tackle on Van Bommel.
Insigne almost intercepted a Marcelo back-header to his goalkeeper and Blerim Dzemaili drilled over, while PSV have penalty appeals for a Federico Fernandez challenge on Jeremaine Lens.
Antonio Rosati needed two fine saves to deny Lens, who had skipped past Fernandez, and a Van Bommel screamer.
However, the goalkeeper got it all wrong when he mistimed his run off the line to gather a long ball, clattered into teammate Fernandez and allowed Lens to roll into an empty net.
Milan transfer target Strootman horribly wasted the chance to go 2-0 up after peeling away from Salvatore Aronica, as he fired the Lens assist wide of the target.
The Napoli defence was shambolic in Eindhoven and Paolo Cannavaro desperately cleared before Lens could pounce from close range. Rosati also needed a great save to deny Atiba Hutchinson.
It really was one-way traffic and PSV doubled their advantage before the break when Luciano Narsingh got past two Napoli players down the right and crossed for Dries Mertens to volley in at the back post.
Walter Mazzarri saw his team in trouble and threw on Edinson Cavani for the disappointing El Kaddouri. PSV remained dangerous and Marcelo nodded just wide from a corner, while Lens got away from Fernandez and Aronica, stopped clear on goal by a desperate Cannavaro.
The substitution made little difference, as Marcelo put the Dutch side 3-0 up when left totally unmarked to turn in a Mertens corner.
Insigne did create a chance for Napoli with his inspired pass to send Cavani clear, but goalkeeper Boy Waterman was crucial in a one-on-one.
Mertens threatened a fourth and Lens again got away from the dismal Fernandez, but preferred an assist for Van Bommel rather than going for goal himself and the chance went begging.
Rosati denied Lens, Mertens and Toivonen just to keep the scoreline remotely respectable, but it was most definitely an off night for the Partenopei.
PSV 3-0 Napoli
Scorers: Lens 20 (P), Mertens 41 (P), Marcelo 52 (P)
PSV: Waterman; Hutchinson, Derijck, Marcelo, Bouma; Van Bommel, Toivonen, Strootman; Narsingh, Lens, Mertens
Napoli: Rosati; Fernandez, Aronica, Cannavaro; Mesto, Dzemaili, Donadel, Dossena (Zuniga 73); El Kaddouri (Cavani 46); Insigne (Pandev 63), Vargas
Ref: Tudor (ROU)