André Villas-Boas's attempt to rescue Chelsea's season is being sabotaged by José Mourinho's continued contact with his former players, according to the president of Porto.

Jorge Nuno Pinto da Costa, who gave Mourinho and Villas-Boas their big breaks in management, claimed the latter could not succeed at Stamford Bridge unless Mourinho cut all ties with the squad.

Pinto da Costa told La Gazzetta dello Sport of Villas-Boas: "He will be successful with Chelsea because his contract isn't just for one year.

"He needs time to mould his own team and he can't do that as long as there are players, as I've heard, who exchange text messages with Mourinho. And [Roman] Abramovich knows this."

Despite Villas-Boas's record as Chelsea manager being worse than any of his predecessors since Abramovich became the owner, the club have repeatedly insisted his job is not on the line.

Pinto da Costa said: "The only thing that will topple Villas-Boas is if he fails to qualify for the Champions League."

The Porto president believes Villas-Boas's future prospects would not be damaged by the sack. He said: "If he leaves Chelsea, he'll be the next coach of Inter."