Fikayo Tomori is one of four Chelsea academy graduates to trade Championship football last season for competing at the highest level in Europe this term.
The 22-year-old centre-back was on loan at Derby County with Mason Mount a year ago, while fellow graduates Tammy Abraham and Reece James were at Aston Villa and Wigan Athletic, respectively.
What a difference a year makes, with the quartet now establishing themselves in a Chelsea side that sit in fourth place, have reached the Champions League last 16 and are in the quarter-finals of the FA Cup.
"It's a big transition"
The climb up the football pyramid, from the academy to the Championship and now to the top-flight in the space of three years has not been an easy one and Tomori told the Chelsea website how he managed to adapt to the transition.
"You’re suddenly thrust into this men’s team environment and playing against seasoned professionals who have played the game for 15 or 20 years in some cases," he explained.
"It’s a big transition because you have to train well, try to get yourself into the team and then you’re fighting every week for three points that could get you promoted, into the play-offs or save you from relegation."
The England international's year with Derby was his third successive spell in the second division having spent the previous campaign with Hull City and the 2016/17 season helping Brighton & Hove Albion to an automatic promotion.
"You have to deal with the physical side of the game but then from the Championship to the Premier League, it’s a bit more of a mental change where you have to be even more focused," he continued, describing the differences between the two divisions.
"You have to be more conscious with how you take care of your body and the little things you can do to improve to get yourself that extra five per cent.
"Each milestone and level has its own adaptation period where you have to figure out what you need to do and how you can better yourself."
"Everybody knows that if you make a mistake in the Premier League, you’re likely to get punished"
Tomori's Blues' debut came in the UEFA Super Cup final against Liverpool, coming on from the bench to play the last 35 minutes against Jurgen Klopp's fearsome strikeforce of Mohammed Salah, Roberto Firmino and Sadio Mane.
Two weeks later the defender made his first start at home to Sheffield United who posed a very different type of challenge, earning themselves a 2-2 draw.
"It is tough because you come up against different strikers and different systems that teams use.
"Some teams might play two strikers up top, some may play one and then you have teams like Liverpool - we all know how Roberto Firmino likes to drop in, with Mo Salah and Sadio Mane running in behind so you need to have that concentration all the time.
"It’s about always being aware of what’s going on around you, communicating with team-mates around you to help them and make your job easier.
"Everybody knows that if you make a mistake in the Premier League, you’re likely to get punished so being able to stay focused and making sure you do everything at 100 per cent is another part that you have to grasp quickly."