Dries Mertens has joked that he intends to give Gonzalo Higuain a "slap round the face" when Napoli meet Juventus this weekend.
Mertens and Higuain are close friends from their days as colleagues in Naples, but the Blegium winger said that would be put to one side as Napoli attempt to narrow the gap on the league leaders.
"I'll give him a slap round the face," he told Mediaset television after scoring in Napoli's 2-0 win over Empoli on Wednesday.
"There is no such thing as friends on the field. It's an extremely important game."
Coach Maurizio Sarri, meanwhile, said he would greet Higuain "like I would a son who has annoyed you."
Napoli trail Juve by four points going into the top-of-the-table clash, with Mertens filling the void left by injury to Arkadiusz Milik.
But Sarri, who has no recognised striker with Monolo Gabbiadini suspended, said: "He's not a real centre forward.
"He needs to play with his characteristics. We don't have any real centre forwards right now, so we have to adapt."