It was Klose who recorded the first goal of the game though, the veteran German finishing low after a run and pass assist from Felipe Anderson.
Things then quietened down until after the break, David Lopez hitting the bar for Napoli with a header after rising unchallenged. Manolo Gabbiadini then had a deflected shot just tipped around the post, before grabbing the equaliser.
Huguain rounded Berisha but his shot his was heading wide until Gabbiadini arrived at the far post to poke the ball home.
Things then started to heat up and both Klose and Raul Albiol were booked for clashing together after a rough challenge from the latter.
It was end-to-end stuff with Klose once again involved in the action, along with Jonathan de Guzman. Napoli were getting on the wrong side of the referee though, with Gabbiadini, Giandomenico Mesto, and Gokhan Inler the latest players to be booked.
The second leg will take place on April 8 at Stadio San Paolo.