The Serie A powerhouse have named previous Italian national team manager Luciano Spalletti to lead the team until the end of the season.
The 66-year-old replaces Igor Tudor, who was dismissed post the Lazio setback on Sunday.
Tudor arrived at the club in March as Thiago Motta's replacement but exited following a seven-month stint following a string of eight matches without a victory.
Spalletti led Napoli to the Serie A title in 2022-23 prior to assuming the Italy role, who had failed to qualify for the 2022 World Cup with Mancini at the helm.
Under his guidance, they made it to Euro 2024 exiting in the last 16 stage against Switzerland.
However, Spalletti was sacked by Italy in June following a loss to Norway in World Cup qualifying, with the Azzurri at risk of missing out on a third consecutive World Cup.
Spalletti's managerial career includes Inter Milan, Roma, and Udinese in Serie A and secured two Russian Premier League titles with Zenit St Petersburg.
Massimo Brambilla served as interim manager for Juventus during the 3-1 victory over Udinese on Wednesday moving them to seventh position in the league - six points adrift of Napoli at the top after nine rounds.
In the Champions League, they sit 25th in the league phase, having lost once and drawn twice in their opening three matches.
