Gonzalo Higuain scored twice against former club Napoli as Juventus booked their place in the final of the Coppa Italia despite losing 3-2 at Stadio San Paolo on Wednesday.

Juve had a two-goal cushion from February's first encounter between the sides and the holders progressed 5-4 on aggregate after a thrillingly chaotic cup clash.

Higuain was on target in his side's 3-1 first-leg win in Turin and, after being approached by a pitch invader armed with a Napoli scarf, he found the bottom-right corner from just outside the box and appeared to celebrate by pointing and shouting angrily at supporters in the stands.

Napoli captain Marek Hamsik prompted hopes of a fightback by finishing off a flowing move early in the second half, but Higuain's powerful shot quickly restored Juve's advantage.

Dries Mertens scored 10 seconds after coming on as a substitute and Lorenzo Insigne struck to set up a dramatic finale, but Juve held out to book a final against Lazio as they seek a third straight Coppa title.

Massimiliano Allegri's men are still on track for the treble as they have a six-point lead at the top of Serie A and face Barcelona in the Champions League quarter-finals.

Juventus opened the scoring after six minutes when the teams drew 1-1 in Serie A on Sunday and they almost made a similarly fast start, only for Alex Sandro to see his shot blocked.

But it was Napoli who created the first big chance after 11 minutes as Arkadiusz Milik's backheel freed Lorenzo Insigne in the left side of the penalty area.

Insigne squared for Jose Callejon, but Neto brilliantly blocked his close-range effort, then Sandro's low drive from long distance was comfortable for Pepe Reina.

Tomas Rincon should have made the tie safe for Juve on the half-hour mark but, when presented with a simple opening by a terrible Vlad Chiriches backpass, he somehow blazed over the crossbar.

That miss was soon forgotten as Higuain, who did not record a single touch in the Napoli box at the weekend, opened the scoring with a superb strike from outside the area.

Stefano Sturaro laid the ball off to the Napoli favourite, who took a touch to set himself and bent an unstoppable low shot into Reina's bottom-right corner.

Napoli needed a goal early in the second half to boost their chances and they got one after 53 minutes.

Hamsik scored Napoli's equaliser against Juve on Sunday and he was again on the scoresheet, placing a shot into Neto's bottom-left corner to give the hosts belief.

Higuain appeared to have extinguished Napoli's slim chances by smashing Juan Cuadrado's right-wing cutback into the roof of the net, but substitute Mertens tapped in with his first touch after Neto allowed a throw-in to squirm under his foot.

Superb play from Callejon presented Insigne with a simple close-range finish after 67 minutes to put Napoli ahead on the night, but they still trailed by a single goal on aggregate.

Allegri made defensive changes to help his side close the tie out and Juve will face Lazio – who beat rivals Roma – in the Coppa Italia final at the Stadio Olimpico on June 2.