#4 Cesc Fabregas (Arsenal): 7-12-04 - 17 years 218 days
Cesc Fabregas scored the third goal in Arsenal's resounding 5-1 home win over Rosenborg in a group-stage game in the 2004-05 Champions League.
At 17 years and 218 days, the Spanish winger became the second-youngest player ever to score a goal in the competition. 15 seasons later, Fabregas remains one of the four-youngest players to have scored in the Champions League.
#3 Mateo Kovacic (Dinamo Zagreb): 07/12/11 - 17 years 216 days
Mateo Kovacic was the lone Dinamo Zagreb player to get on the scoresheet in a 1-7 defeat against French side Olympique Lyonnais in a group-stage game of the 2011-12 UEFA Champions League.
In the process, the then 17-year-old Croatian midfielder overtook Fabregas as the second youngest-ever scorer in the competition.
It was also a game where Bafetimbi Gomis of Lyon recorded the fastest-ever hat-trick in the Champions League.