Hazard, who has also left Chelsea to join Real Madrid, scored 21 goals and provided 17 assists for the Blues across all competitions in 2018-19.
Sarri’s lone campaign with the Premier League outfit will likely be seen as a success in retrospect following a top four finish and the Europa League title but he still faced criticism for his tactics from some quarters this year.
Speaking at his official unveiling Turin, the 60-year-old stated that he believed he was unable to play to the free-flowing 4-3-3 approach he was acclaimed for at Napoli as he felt obliged to play his talismanic striker in his preferred role.
"In recent years, I've had 4-3-3, but the 4-3-3 at Chelsea was very different to the one at Napoli," Sarri stated.
"We had to accommodate Hazard's characteristics, as he could change the game, but also his presence caused issues in defending that we had to work on."
The 28-year-old had enjoyed his most prolific season in a Blues shirt with the boot to conclude his stay in London, having signed for the club in 2012.
Across a seven-year spell, he won all three major domestic honours in English football, including two top-flight titles, as well as a brace of Europa League crowns.
Sarri meanwhile won his first major honour when he guided Chelsea to a 4-1 win over Arsenal in last month’s Europa League final in Baku.