The Italian, who after four years at Stamford Bridge was sacked 12 months into Abramovich's reign in 2004, was saddened by the Londoners' Champions League final penalty defeat to Manchester United.

And the 56-year-old Juventus boss believes that, after the relatively modest outlays of the last two years, significant summer spending is required if Chelsea are to overhaul United as the top English club.

"Now it's important Abramovich continues to invest in this team," said Ranieri, who is in Hong Kong on the Bianconeri's post-season tour of Asia and Australia.

"It's important to continue as he has a very good quality team."

Ranieri is unsure if Chelsea can retain their top players amid speculation of a mass exodus which could see the likes of Didier Drogba and Frank Lampard leave the club, but he believes the latter would thrive in Serie A.

The England midfielder has been linked with a move to Inter Milan and Ranieri said: "I don't know if Frank Lampard will stay.

"But I think players like Frank Lampard can have success in every country."

Ranieri refused to be drawn on speculation linking Liverpool's Spanish midfielder Xabi Alonso with a move to Turin.

"I don't know," he said. "If you tell me something, I can believe it."