Andre Villas-Boas made a mistake joining Chelsea, says Porto president Jorge Nuno Pinto da Costa The other thing that weighed heavily was the difficulties he had in emulating Mourinho's Champions League victory in 2004. He left thinking that Chelsea was a unique opportunity, but I believe that was a mistake because there would have been others. And having claimed Villas-Boas could not match Mourinho at Porto, Pinto da Costa believes the Chelsea old guard - such as John Terry, Frank Lampard and Didier Drogba - are part of the reason he has struggled to live up to his illustrious countryman's achievements at Stamford Bridge. "He's doing well, he qualified for the Champions League last 16 and he's in all the competitions," added the Porto president. 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 (the Chelsea owner) knows this. Although Mourinho has enjoyed great success at every club he's coached - winning two league titles each with Porto, Chelsea and Inter Milan, while adding two Champions League crows with the Portuguese and Italians - he has come under fire at Real Madrid this season, notably for defeats to arch rivals Barcelona. Real may be 10 points clear at the top of the Spanish League and qualified for the Champions League second round with a perfect record - the best of all qualifiers - but that hasn't appeased Madrid fans fed up at seeing their team lose to Barca in direct confrontations. And yet Pinto da Costa doesn't believe Mourinho will be leaving the Spanish capital any time soon to return to his old London hunting ground. Mourinho will stay at Real Madrid next season. The only thing that will topple Villas-Boas is if he fails to qualify for the Champions League," said the Porto president. If he leaves Chelsea, he'll be the next coach of Inter.