With Edinson Cavani starting from the bench, Mbappe led the lines for Thomas Tuchel’s men and Juan Bernat, off the France youngster's assist, gave the visitors the lead before Lorenzo Insigne's penalty secured them a 1-1 draw in Naples.
Two weeks ago, both sides had played 2-2 in Paris with Mbappe also failing to find the back of the net. The Senegal international has, however, explained how he dealt with the ‘superfast’ 19-year-old.
“Well I didn't use any magic potion, I just did my job,” Koulibaly explained to RFI.
“Everyone has strengths and weaknesses, you just have to know how to match up against a player.
“We all know that Mbappe is super fast so I knew that I was going to have to anticipate his next move and that's what I did all game long this past week. It worked well for me this time.”
Despite signing a new long-term deal with Napoli in the summer to ward off interests from top European sides, the defender remains in-demand.
Pleased with the attention he is getting, the 27-year-old, only focused on how things fare in Naples, is keen to continue working to improve himself - and, also to stay relevant.
“I am still working to improve myself. I do not need the transfer window or anything to improve myself,” he said.
“Since I'm a professional, every day I try to become a better player. Today, the fact that some teams are interested in me is pleasant. But for now, I'm totally focused on Napoli.
“I know these are things that should not distract me. Especially since football goes very fast in both directions. Today, we talk about myself positively. But the most important thing is that I remain a quality player.
“So I try to show my qualities for the good of the team. After, we'll see what happens to me. We are very early in the season, I do not need to think about it. For me, the most important thing is that Napoli qualify for the next round of the Champions League.”