"He has never called me, but he always sends me text messages".
The Italian's handling of the Costa situation didn't sit well with Willian, who has claimed his old boss also had issues with David Luiz.
"He said, "I'm leaving, Conte said he doesn't need me anymore". I was in Australia with Brazil and Diego texted me. I said: "What do you mean?" It was a hard situation'.
Willian has been strongly linked with a move away from Stamford Bridge this summer and the newspaper says that with both he and Martial valued at around £75m, a sensational swap deal could be on the cards.
It's clear the South American wants to work with Mourinho again and his comments will only spark further speculation that Willian could be heading to Manchester United before the window shuts later this week.
"I don't think I should comment to much about that in this moment because we are at a delicate time in the process", he said. "I'm joking. I think Conte was, for me particularly, a manager that was hard to work with". So it was a bit hard working with him.
Meanwhile, Pepe Reina has dismissed rumours linking him with a move to Chelsea, saying he is happy to have joined AC Milan, where he hopes to be named number one this season.
Chelsea will open their 2018-19 Premier League campaign with a trip to Huddersfield Town this weekend.