The Belgium has been a revelation since moving from the wing into a central attacking position, netting 13 times in his last eight Serie A games
There were still 15 minutes to go in Napoli's Serie A meeting with Cagliari when Maurizio Sarri decided to give Dries Mertens a well-earned rest. The striker had just completed a hat-trick, yet he asked his coach: "Why are you taking me off?"
Sarri was bemused. "What?! How many did you want to score?!" Quick as a flash, a smiling Mertens responded: "Four!"
In the end, the Belgian would only have to wait seven more days to realise his ambitious aim. Mertens needed just 22 minutes to rack up three goals against Torino on December 18, thus becoming the first player since Juventus' Pietro Anastasi in 1974 to score back-to-back hat-tricks in Serie A.
The best was yet to come, though. With just 10 minutes remaining, he received a pass from Jose Callejon just inside the Torino box, stepped away from Luca Rossettini and then attempted the most audacious chip over Joe Hart in the Granata goal. The England international never even got off the ground. He knew there was no point in even jumping.
Mertens wheeled away in delight, while team-mate Vlad Chiriches simply stood in the centre circle and joined in the applause for the kind of goal not seen at the San Paolo since the days of Diego Maradona.
The 29-year-old wisely distanced himself from such comparisons after the game. "I've still a bit of work to do to be like him!" he pointed out. Mertens may not be the 'new Maradona' but he is the new darling of the San Paolo, having come to Napoli's aid in another time of need.
When Arkadiusz Milik suffered a knee injury on international duty in October, Partenopei supporters feared the worst. The Poland striker had been signed to replace Gonzalo Higuain, who had defected to Juventus last summer, and had made an impressive start to filling the Argentine's boots, netting seven times in his first nine outings in all competitions.
With Milik sidelined, Sarri turned to back-up No.9 Manolo Gabbiadini. However, the former Sampdoria striker flopped in Napoli's first outing after the international break, against Roma, and was then sent off just half an hour into the subsequent meeting with Crotone.
Sarri was out of genuine centre-forwards, so he decided to trial a 'false' one, putting Mertens in-between Lorenzo Insigne and Jose Callejon to form a small but skilful attacking triumvirate. The tactical tweak has brought the best out of all three players.
Perennial under-achieve Insigne is in what Sarri says is the best period of the Neapolitan’s career, while no player across Europe’s ‘Big 5’ leagues has created more goals (9) this season than Callejon.
It is Mertens, however, who has been the star of the greatest show in Serie A (Napoli have already racked up a club-record 55 goals in 23 games, which is seven more than leaders Juve), with the former PSV winger having struck 13 times in his last eight league games alone.
The Leuven native hasn't just caught fire in Italy, though. Nobody has played a bigger part in Napoli reaching the last 16 of this season's Champions League than Mertens, who has scored four and created two of the Partenopei's last eight goals in the competition.
Unsurprisingly, he stepped up when they needed him most, too, setting up Callejon for the opener in their crunch clash with Benfica before scoring the goal that ultimately decided the game - and Group B - in Napoli's favour.
Sarri had always believed that Mertens had the ability to play as a centre-forward. He had only doubted whether the player himself believed he could fulfil the role.
"I deserve little credit for Mertens' form," the Tuscan insists. "He's a great player who in the past didn't realise the quality he had at his disposal.
"My only problem is coaxing consistent performances out of him, because throughout his career he's always had dips after a great moments.
"He must convince himself that he is world class."
Mertens, though, is clearly starting to believe in himself. Certainly, there was a swagger about the way in which he tore Bologna apart last weekend. He opened his account at the Dall'Ara by curling home a free-kick with the kind of nonchalance that suggested he fully expected to score, while there was never any doubt as to who would come out on top when he twice went one-on-one with Rossoblu goalkeeper Antonio Mirante to complete his third treble in three months.
Most tellingly of all, though, a shy character who shuns the spotlight and dislikes doing interviews has spoken bullishly about Napoli's hopes of upsetting Real Madrid at the Santiago Bernabeu on Wednesday.
"We've become a great team and the fact that we're in the last 16 proves it," Mertens declared. "We're not afraid of them." It is Real who should be afraid of him.