Porto president Pinto da Costa says Chelsea boss Andre Villas-Boas is being undermined by senior players' still being in contact with Jose Mourinho. Da Costa also claimed Blues owner Roman Abramovich was aware of the situation.

Real Madrid boss Mourinho was linked with a return to Chelsea last week.

Pinto da Costa said: "I'm not at all disappointed with how Villas-Boas has done. He's doing well, he has qualified for the last 16 in the Champions League. He's still in contention for everything.

"He will have success with the Blues because his contract isn't only for one year.

"He has to have time to mould his team and he cannot do that while there are players who, as people say, exchange text messages with Mourinho. Abramovich is aware of this."