#3 Reece James
There was never any doubt about Reece James' abilities and talents as the Englishman moved up the ranks in Chelsea's youth teams. He was earmarked for success at a very young age, and his performances for Chelsea in recent years have lived up to expectations.
James is typically a right-wing back and is equally strong in offense and defense. He has been excellent in the current campaign and had started brilliantly before a major injury put him in the recovery room.
Although the opponents were Grimsby Town, James showed the world what he is made up of during his full debut. Chelsea ran riot by demolishing the League Two club 7-1 in the EFL Cup, and James had the biggest say in that.
He was rarely challenged in defense and was always two steps ahead of the opposition. His attacking talent was on full display during his individual goal and the two more goals he helped set up.
#2 Tammy Abraham
Chelsea have endured plenty of misfortune when it comes to the centre-forward position. Following the retirement of Didier Drogba, the club couldn't manage to find a suitable successor until Tammy Abraham came up through the ranks.
Following a spell of successful loan spells in the championship, Abraham was ready for the big stage. His first debut was in the 2019 UEFA Super Cup, where he came off the bench to win a penalty that led to a Chelsea goal.
However, he missed his penalty kick in the shootout and received ugly racial abuse on social media. However, it didn't deter Tammy, as his moment of redemption came very soon.
On his first full debut away to Norwich, Chelsea managed to win 3-2 largely thanks to Abraham. He scored two goals and was the main difference maker between the two sides, and the next few months for him were excellent.
After that, however, the goals dried up, the inconsistencies rose, and he was sold to Roma. Abraham has started brightly for the Italian club under Jose Mourinho, and he will hope to deliver on the promise he has always had.
#1 Ryan Bertrand
It's quite hard to imagine that any teenage footballer will hope to make their senior debut in any competition, at one of the biggest and toughest matches in football. But it was a reality for Ryan Bertrand, who made his full Champions League debut in the 2012 final against German giants Bayern Munich.
He became the first footballer to make his senior debut in a final in the Champions League era. It's to be noted that Bertrand had already made his full debut in other tournaments, but it was his first in Europe's premier club competition.
Bertrand played for 70 minutes and was quite agile in tackling the attacking threats of Bayern Munich. Sadly, he could play only 70 minutes before getting down with a knock. The brilliant start to his Chelsea career didn't turn out to be sustainable as the player was sold to Southampton after a couple of loan spells. But overall, the Chelsea graduate has been a consistent player in the Premier League.
Bertrand tops this list purely because he was called in to make his European debut in the final moments leading up to possibly the biggest ever game in Chelsea's history. To be fair to him, he did exceedingly well too, albeit playing in an unnatural position.