The former Blues boss has fired a warning to the club not to expect the same results from the Special One's first stint in charge at Stamford Bridge after his return was confirmed.
Former Chelsea coach Ruud Gullit believes Jose Mourinho will struggle to match expectations at Stamford Bridge in his second stint as manager.
The Special One guided the Blues to back-to-back Premier League titles, the FA Cup and two League Cup trophies during his first spell in charge between 2004 and 2007, and penned a four-year deal to return to west London on Monday.
But Gullit, who managed Chelsea between 1996 and 1998, insists Mourinho will find it tough to replicate the success of his previous spell despite his obvious connection to the club.
"Is it a good idea for him? I don't know. There is the same chemistry between him and the fans, yes," he told the Daily Star. "But the coaches who are less expected to do something win everything, the big prizes, so it's a very difficult situation for him.
"He is one of the best coaches there is. But can he do it, can he do it again? We are going to see."
Having failed to deliver the Champions League during three years at Real Madrid, Mourinho has been deemed a failure in Spain by some and Gullit believes the Portguese has a big point to prove.
"You have to wonder if he'll be different after Madrid," the former Netherlands international added. "He was not as loved as he was in England, that's for sure. But what surprised me more was that Mourinho's biggest asset is his psychological work with his players. He makes them win things for him but he couldn't do that with Madrid, and that was strange because it's his strongest skill.
"I think he will be very keen on doing well here but I just think it's the ones who are less expected to who end up winning the best prizes."