A crucial moment came early in the game when Ajax's captain, Kenneth Taylor, received a red card in the 15th minute, giving Chelsea an advantage.
Just a couple of minutes later, Marc Guiu, who is 19 years old, scored the first goal for Chelsea, marking a new record as the team's youngest ever Champions League goalscorer.
Moises Caicedo added to the lead, and Enzo Fernandez made it 3-1 from a penalty kick.
Before halftime, Chelsea was awarded another penalty, which Enzo Fernandez gave to Estevao, 18, who scored and broke the record set by Marc Guiu just 30 minutes earlier.
Chelsea continued to dominate in the second half, with Tyrique George, 19, scoring his first Champions League goal.
This achievement made Chelsea the first team in Champions League history to have three teenagers score in the same game.
