The Serie A table-toppers were struggling to find a cutting edge as André-Frank Zambo Anguissa directed a tame header into the grateful arms of Cezary Miszta when he really should have scored. At the other end, Juan Jesus got away with a shove in the back of Lirim Kastrati on the edge of the area after the winger had latched onto a pass forward.
Napoli needed to respond, and after surviving a scare when Yuri Ribeiro’s long-range effort struck a post, Zieliński won a penalty early in the half after being barged in the back by Josué. The 27-year-old drove his spot-kick confidently past Miszta to equalise, but the contest still hung in the balance going into the last 20 minutes, as Mertens entered the fray.
The Belgian didn’t have to wait long to be involved, as barely a minute after his arrival, Josué gave away his second penalty of the evening after allowing the ball to take a fatal bounce in his area and catching Matteo Politano with an attempted acrobatic clearance. Mertens produced a Panenka-esque finish to turn the game on its head, and his next involvement saw him set up the third, his inch-perfect pass round the corner releasing Andrea Petagna, who calmly squared for Hirving Lozano to finish.
Adam Ounas made it four in stoppage time, expertly switching the ball onto his right foot to volley home. In a huge turn of fortune, Luciano Spalletti’s men now sit a point clear of their hosts, who will drop to third if Leicester City beat Spartak Moscow in the other group game later today.