Kalidou Koulibaly, Napoli's French monster in defense

When Napoli announced their first signing of the summer, no one was quite sure what to make of it. Kalidou Koulibaly was, at the time, a French defender plying his trade with a good-but-not-great Genk side in Belgium's top division, and a relative unknown. Those who follow youth football may have recognized him from his 11 caps with the French U-20's, but even that was some time ago as Koulibaly was 23 by the time the transfer window opened.

Koulibaly was raw. Very raw. He'd had flashes of brilliance with Genk, but spent most of his final season there in frustratingly inconsistent form. It looked like the defender would be a project for Napoli, and at a reported €7 million price tag, it seemed like Napoli had potentially bet too high on this one given the summer's limited budget.

Then he started in a friendly against Barcelona, and was arguably the best player on the pitch. Then he did the same thing against Paris Saint-Germain. Against Athletic Bilbao, he was one of the few good things Napoli had going in a dire tie. When Serie A finally started, so continued his run of impressive matches. Genoa. Udinese. Palermo. Sassuolo. Sparta Prague in the Europa League.

Kalidou Koulibaly has risen from an obscure curiosity to a force in Napoli's defense in a matter of just a few months. After a couple slightly off performances, though, many were wondering how he'd perform against Roma's vaunted attack going in to yesterday's derby match.

Instead of succumbing to doubt, however, Koulibaly put in a masterful performance of a quality rarely seen by a defender. He was all over the place in Napoli's defense, calmly keeping Francesco Totti and then Mattia Destro at bay while flying around blowing up other attacks, clearing danger, and cutting out through balls. He was excellent in the air, excellent on the ground, and excellent covering set pieces.

It was, in short, one of the best performances you'll see by a defender this season.

Koulibaly is tall, strong, and extremely athletic. While those are all excellent traits for a defender to have, they're not enough on their own. An ability to read what's going on ahead of him is just as vital as any physical gifts, as being in the wrong place or heading in the wrong direction means that all those gifts would be about as useful as a heating pad at noon in the Mojave Desert.

Fortunately for Napoli, Koulibaly reads the game very well. And what he has that's possibly even more valuable is an almost preternatural instinct to do exactly what needs to be done, where it needs to be done, and how to needs to be done. That instinct has helped Koulibaly bail Napoli out of several jams this season, keeping holes from getting deeper, or from even getting dug in the first place.

Already, after just a few months with the club, some are starting to talk about Koulibaly as one of the best defenders in Italy. It's quite an ascension from where he was not too long ago, but he's earned every bit of the appraise he's been given. Napoli have found themselves a potentially special defender; Riccardo Bigon and his staff should feel proud for finding him, as well as Rafa Benitez and the coaches for unlocking his talent.

Napoli don't just have a rock in the heart of their defense, they have a monster patrolling the back line gobbling up any attack that comes near. That beast's name is Kalidou Koulibaly. Fear him, for he is terror incarnate.