New Chelsea boss Frank Lampard says returning to his former side as manager is the biggest challenge of his career.
The 41-year-old ex-England midfielder was appointed on Thursday by the club where he spent 13 years as a player.
Lampard had been in charge of Championship side Derby - his first job in management - for 14 months.
"I am not naive. I understand fans want success. I don't see this as a risk. I am not fearful of the downsides," he said.
When asked if taking charge at Stamford Bridge, where he has legendary status and is the club's all-time leading goalscorer, will be the biggest challenge he has faced, Lampard replied: "Yes."
He added: "Coming here 19 years ago was a challenge. I had the radio on and some people were questioning whether I should be here for £11m.
"I thought last year was a huge challenge."
'Not an old boys' club'
Jody Morris, another former Chelsea midfielder, has moved from Derby with Lampard to take up the assistant coach role at Stamford Bridge.
Ex-Blues coach Chris Jones returns to the club, while former Chelsea midfielder Eddie Newton and under-23s coach Joe Edwards will also join Lampard's backroom staff.
Former goalkeeper Petr Cech, who played for Chelsea between 2004 and 2015, returned in June as the club's technical and performance advisor, while Lampard's former team-mates Didier Drogba and Claude Makelele have been linked with returns.
"It's a very Chelsea-orientated team but what I want to make clear is this is not an old boys' club," said Lampard.
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Lampard ready to prove his worth
Lampard, who made 649 appearances for the Blues, retired from playing in February 2017 before taking his first steps in management with Derby in May 2018.
He led the Rams to sixth place in the Championship, before they were beaten 2-1 by Aston Villa in the play-off final.
Despite Lampard's status at Chelsea, this move so early in his managerial career has been seen by some as a risk, especially for a club which has had four different managers in the past four years.
Lampard added: "I know it is an obvious question and I understand it.
"What I do believe is that I played under a lot of fantastic managers and learned a lot, and I think that stands me in good stead.
"I learned a lot at Derby and I know this club and how it works - but I have to prove that."
|Lampard's record at Derby|
|Competition||Games||Won||Drawn||Lost||Goals for||Goals against||Win %|
|Championship (inc. play-offs)||49||21||14||14||74||59||42.9%|
Chelsea finished third in the Premier League last season and won the Europa League under Maurizio Sarri, who left to take over at Italian champions Juventus in June.
Lampard has not set any targets for the coming season but accepts a top-four finish in the league will be the minimum expectation from fans.
"We have to start with an intention to win," he said. "If I sat here and didn't say that then I shouldn't be here.
"We want to play Champions League football year in and year out."