Goals from Arkadiusz Milik, Fabian and an own goal from Jerome Onguene handed Carlo Ancelotti’s men a first-leg advantage at San Paolo.
The Senegal international who featured for the entire duration of the tie was impressive, helping the Parthenopean keep a clean sheet - their fourth in five games.
Following the imperious display, the 27-year-old took to the social media to show his excitement while looking forward to the return leg with lots of hope.
“Beautiful victory and important result. Good to not concede goals and to make three,” Koulibaly tweeted.
“But it's not over yet, the qualification is played on the return.”
Bella vittoria e risultato importante: bravi a non subire gol e a farne tre. Ma non è ancora finita: la qualificazione si gioca al ritorno. Fiducia nei miei #fratelli: mille per mille 🙌🏿— Koulibaly Kalidou (@kkoulibaly26) March 7, 2019
🇮🇹 #NapoliFCS 3-0 🇦🇹
🇸🇳 #KK26 #famiglia
💙 #ForzaNapoliSempre #DifendoLaCittà 💪🏿 pic.twitter.com/sd86JplMo2
Koulibaly who has made 32 appearances for Napoli this season will hope for another commanding display when they visit Sassuolo in their League game on Sunday.