The Italian was replaced by Carlo Ancelotti while he was still under contract with the Serie A club
Maurizio Sarri discovered he was no longer Napoli manager by watching the news break on television.
The 59-year-old took over at Chelsea after complex negotiations to leave the Italian club finally ended.
Sarri had two years remaining on his contract at Napoli after running Juventus close to the title last season.
He was still under contract when Napoli appointed Carlo Ancelotti as their new boss, as Chelsea struggled to agree a compensation package with the Serie A side.
And as he waited on his next move, the 59-year-old’s legal dispute finally came to a conclusion that allowed him to complete a deal to Stamford Bridge.
Speaking to Il Mattino, he said: “It’s true, I found out that I wasn’t the Napoli coach anymore by seeing it on television.
“I had some doubts, that’s fair, but there was a clause in the contract and it wasn’t something I had asked for.
“It was not respected in the timing. Now I hope that Ancelotti can achieve what I came so close to.”