Kai Havertz hailed the impact Thomas Tuchel had on his career, with the new Bayern Munich boss having coached the Germany international at Chelsea.
Tuchel, who was announced as Bayern's coach following the shock sacking of Julian Nagelsmann last week, took charge of the Blues between January 2021 and September last year.
The German guided Chelsea to Champions League glory in 2021, with Havertz scoring the first-half winner in a 1-0 victory over fellow Premier League side Manchester City.
Speaking to The Guardian on Tuchel's influence, he said: "Tuchel gave me a different idea of football.
"Every detail counts, every centimeter, how you touch the ball, how you control, where you pass, which foot, movement, creating spaces: he's just top level.
"To come and win the Champions League in six months says it all.
"My brother and I used to watch every Champions League game and to hold the trophy with your family on the pitch was such a relief.
"I scored this goal, I can be happy. I made my childhood dream come true."
Chelsea remain in this year's competition after overturning a 1-0 first-leg deficit to Borussia Dortmund with a 2-0 home win at Stamford Bridge.
Havertz scored the crucial second goal from the penalty spot and his side now face reigning champions Real Madrid in the quarter-finals.
"The ambition is still there," Havertz said about Chelsea's Champions League aspirations this campaign.
"In the league, we are not very good and we feel for the fans but against Dortmund, the atmosphere was the best I have seen. You feel the excitement.
"The Premier League is big and winning it may be even more difficult but the Champions League is different. Hearing that anthem, playing at night, it's special."
Despite progress in the Champions League, Tuchel's successor Graham Potter sees his side sit tenth in the Premier League and 11 points off a top-four position heading into the final stage of the season.
Regardless of the pressure on Potter and the new singings brought in as part of an ambitious January spending spree, Havertz believes all of them will thrive at the club given time to develop.
"Potter is very good for Chelsea even though he gets criticism; in the changing room, everyone knows his qualities.
"Enzo [Fernandez] and [Mykhaylo] Mudryk have come for a lot of money and they're only 22, you know? You cannot expect them to be Neymar straight away. It's like me: it takes time."