Napoli coach Rafael Benitez has said his side could not have been given a more difficult path to the group stage of the Champions League after they drew Athletic Bilbao.
After becoming the first side not to qualify from their group despite gaining 12 points last year, Napoli host Athletic in the first leg of the playoff before travelling to Spain a week later.
Benitez said his side would have to be at their best to get through, telling Napoli's official website: "Certainly, of the five potential opponents, Athletic are the most difficult we could have got.
"They play good football and have 50,000 fans behind them at the San Mames, which gives them a huge lift. It's going to be a cracking game -- a very intense duel -- but Napoli are ready and determined to reach our objective."
Napoli will be desperate to ensure that three Serie A clubs appear in the Champions League next season, the other two being Juventus and Roma.
Serie A fell behind Portugal in UEFA's five-year rankings this summer, and risks losing further ground on the top four leagues without an improvement in European results.