The rise, fall and rise again of one of the Premier League's most sought-after young goalkeepers has been fairly remarkable over the past 12 months.

Not so long ago Sanchez was talked about as one of the top-flight's rising stars, a giant of a man with an excellent command of his box, a strong shot stopper and comfortable with the ball at his feet. The all-round modern goalkeeper.

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But a poor spell at the Amex last season, tied in closely with the ultra-prescriptive style of incoming manager Roberto De Zerbi, brought everything tumbling down. Memories are short in football and within months, after losing his place to Jason Steele in March, the 25-year-old's stock had collapsed.

The £25m offer Brighton accepted from Chelsea in August would have never been countenanced a year earlier. Bayern Munich were said to be stunned by the price tag and also sounded out a move.

Now thrust back into the spotlight under Mauricio Pochettino and surrounded by £1bn worth of players, it has given Sanchez a chance to rebuild the reputation he worked so hard to develop.

Between his first and his last Premier League appearance for Brighton, only seven goalkeepers kept more clean sheets. Only Alisson and Ederson completed more passes, and only Nick Pope and Emi Martinez made more catches.

Those aren't the statistics of a bad goalkeeper. Others' confidence in him dropped off, but Sanchez has long talked about the sense of self-belief which first helped him oust fan favourite Mat Ryan as Brighton No 1, and has now seen him through the other side of a tough few months before his London move.

"If you don't believe in yourself, who else will?" He asks Sky Sports, half smiling, at Chelsea's Cobham training base. "I think I did well last season.

"He [De Zerbi] had a view of the team, for one reason or another he didn't count on me for the specifics of the kind of goalkeeper he wanted and decided to go with another [Jason Steele].

"He suited what he wanted to do better, and I'm happy for him, because he'd been supporting me for the two and a half years I'd been the goalkeeper and now he's got his chance."

De Zerbi hinted at similar when he first dropped Sanchez in March. Though the Italian never expanded on the details, Steele's success on the ball in his press-baiting style made it clear.

Sanchez's form had suffered too before he lost his place. He conceded more than five goals over his expected tally last season, but he didn't become a poor player overnight.

"I was pretty relaxed," he adds. "I know my level as a goalkeeper. I know I'd play one way or another somewhere, so I relaxed and waited for my opportunity to come round."

Could he have imagined sitting here as Chelsea's No 1 at the start of the summer, though? "I probably couldn't have seen that coming," he laughs.

"You hear things as the transfer window goes on, and when Chelsea got in touch I couldn't say no. What they presented for me, the plan that they had, it was unbelievable."

It helped that Levi Colwill, a stalwart in the Brighton backline last season, had already returned to his parent club Chelsea and would be a familiar face waiting for him at Cobham.

He wasn't the only one. Ben Roberts, Sanchez's goalkeeping coach for his entire Brighton career, moved to Stamford Bridge with Graham Potter last year and stayed on after the head coach's short-lived tenure. There was the lure of working under Mauricio Pochettino, too.

"The whole thing just looked like a real family environment here," he says. "There was Ben [Roberts] and the relationship I used to have with him, Moises Caicedo, [Marc] Cucurella, Levi [Colwill], a couple of Spanish talkers.

"Ben knows my level, he always thinks I'm one of the best and he helped with the move - he put a good word in and helped to get me to Chelsea. I love him, I've had an amazing relationship with him for seven years, and I wanted to come here and work with him.

"I'd played against a lot of the boys for a few years - and I also had a couple of chats with the manager, I know what kind of manager he is.

"He knows when to tell you that you need to do better, when to give you a hug, put his arm around you. He's a great manager tactically, but especially managing players, he gets to know each player individually and everyone's different, and he gets the best out of us."

The rebuild of Sanchez's reputation as one of the Premier League's best will take longer than his return to first-team football. It is not helped by the expectation levels on a squad still finding its feet in front of the world's glare and a line-up still being tinkered by Pochettino.

He has witnessed first hand the virtues of time and patience under Potter at the Amex though he knows, as the head coach found out for himself in April, those qualities are not often in great supply at Stamford Bridge.

"We've got a great manager, great staff, wonderful individual players, but it's a young team," he says. "People have heard this a lot of times but players have come in from a lot of different situations, it's new to them, and we need time.

"We're improving as quick as we can, we know we want to win but it does take time. Winning is the most important thing, it gives us the best feeling, but we'll get there."

An much-needed shot in the arm could come at the Vitality Stadium this Sunday, live on Sky Sports, against a Bournemouth side still without a win this season.

Whatever the outcome there, for Sanchez at least, it won't be for a lack of belief.

Watch Bournemouth vs Chelsea live on Sky Sports Premier League from 1pm on Sunday, kick-off 2pm