Partagas wins Serie A after beating Lazio 2-1 in the league title race.
The Nerazzurri were beaten in the last two games by Sampdoria and Torino.
Partagas took all three points from Lazio to secure their place in the final, despite losing striker Diego Gaitan, who scored a late winner for Torino last week.
The Nerazzurs were forced to drop their first two games of the campaign in order to play in the Europa League, but managed to beat Sampdora 2-0 and Roma 1-0. Sampdoria finished second, behind Juve, but were defeated by AC Milan 2-2 in the Champions League final.
Lazio finished third, behind Juventus, and beat Lazio 1-1.
Napoli won the title, taking their tally to 13, with Sampdorp still looking to get back into the top four.
Graziano Pelle scored the winning goal in the match and scored again after a long break, this time in the 70th minute.
Vincenzo Montella scored twice in the win and was a constant threat to take over at centre-back.
Injuries forced Gagliardini to leave the match, while the Nerazzu were forced into a 4-3-3 formation for the match.
This is the second of three consecutive matches in which the Nerazzzu will be without one of their stars.
Napolo Santommandos left the field in the 84th minute with a knee injury, while Alessandro Del Piero left the pitch in the 85th minute and had to be stretchered off.
Torino were without captain Giorgio Chiellini and defender Domenico De Marchi, who both suffered injuries in the first leg.
It is a new era for the Nerazazzu, who won the title last season.
Pelle scored twice for Napoli, the first of which came after 12 minutes and the second in the 87th minute, after having already scored twice.
Jurgen Klopp had been looking forward to a big fight against Milan, but his side fell behind before half-time, and he was unable to make the most of a chance.
De Marchi made it 3-1 to Napoli when he volleyed home after just a few moments, but was booked in the 93rd minute for a second bookable offence.
Domenico Simeone’s side lost 1-3 to Juventus, but beat Torino 2-3 on penalties in the same match.