Endrick scored his first Real Madrid goal as Carlo Ancelotti's side claimed their first win of the LaLiga season after beating Real Valladolid 3-0.
Federico Valverde and Brahim Diaz were also on target for Los Blancos, who struck three times in the second half despite a generally lacklustre display at Santiago Bernabeu.
After a goalless first half, Madrid broke the deadlock within five minutes of the restart, as Valverde thumping a vicious 25-yard free-kick through the Valladolid wall and beyond goalkeeper Karl Hein.
The reigning LaLiga champions had to wait until the 88th minute to establish breathing space with substitute Diaz latching onto Eder Militao's long ball and slotting home.
Endrick, who also climbed off the bench, added gloss to the scoreline deep when he rounded off a swift counter in the sixth minute of stoppage time.
The teenage dream comes true for Endrick
Entering the contest as an 86th-minute substitute, Endrick took just 10 minutes to announce himself to Santiago Bernabeu with his new side's third goal.
At 18 years and 35 days old, the Brazil international became the youngest Madrid player to score on his LaLiga debut in the 21st century, and the first foreign player to achieve the feat overall.
His effort was provided by Diaz, who scored and assisted in a single match in any competition across Europe's top five leagues as a substitute for the first time in his career (207 appearances).
Los Blancos have now won each of their last six league meetings with Valladolid without conceding, while their opponents have lost on four successive trips to the Spanish capital for the first time since a run of six in November 2012.