The former Chelsea man lifted the champion’s trophy under the special one’s direction at porto, and he believes he will get success with Red Devils.
Despite of a difficult start of this season deco thinks that jose Mourihno will get succeed at Manchester United.
The special one has suffered two straight premier league losses, it raises some doubt, as United are six points behind of their arch rivals Manchester city.
But deco played under the Portuguese and believes that he will prevail.
"He has the attention to detail, there will still be details that he needs to get right at Manchester United, but he will get the club to where he demands them to be.
"You have to remember this is a team who finished outside the top four last season but, because Mourinho is there, people expect them to suddenly be competing for the league."
The former Portugal International thinks that Mourihno needs some time to settle down as they buy such heavy named player this year like Henrikh Mkhitaryan and Paul Pogba.
"Football doesn't always work like that, new coaches need time, and new players need time to settle," he said.
"The most important thing this season is that Manchester United finish in the top four and are back in the Champions Leauge.
"Mourinho has always taken the domestic cup competitions seriously whatever league he has been in - and I think he will really try and win one this season.
"This Season was always going to be a season of transition and a top-four finish and a domestic cup would have to be considered a success."