Napoli coach Rafa Benitez isn't surprised by the impact of Jose Callejon.
The former Real Madrid winger arrived in the summer and struck again in victory over Catania.
"Jose Callejon, Lorenzo Insigne and Dries Mertens are interchangeable, as they are all at a very high level and come back to help the defenders. That's why 100 per cent fitness is important and I have to rotate when playing every three days," said Benitez.
"I knew Callejon was someone who worked hard, listened and helped the defence as well as creating chances to score."
