The 18-year-old substitute George Ilenikhena sprinted onto Vanderson’s long ball over the defense in the 71st minute, unleashing a powerful shot past Marc-André ter Stegen.
Eric Garcia received a straight red card just 10 minutes into the match for fouling Takumi Minamino as the last man, following a poor pass from Ter Stegen.
Monaco took the lead shortly after when Maghnes Akliouche calmly slotted the ball past a stationary Ter Stegen.
Barcelona’s teenage sensation Lamine Yamal equalized with his first Champions League goal, seizing a long ball, cutting inside, and driving a low shot into the bottom corner.
However, Ilenikhena’s goal, his first since joining from Royal Antwerp this summer, sealed Barcelona’s opening defeat.
Vanderson nearly added to the score with a strike from the edge of the area that was pushed wide, while Minamino’s effort was deflected onto the crossbar.
The win could have been even more convincing, but Folarin Balogun had a penalty overturned late on after a VAR review determined he had gone down too easily following a challenge from Inigo Martinez.
Ilenikhena outshined Yamal as the two teenagers made history. Coming off the bench in the 59th minute, he found the net just 12 minutes later, securing victory for his team.
His composed finish made him Monaco’s youngest goalscorer in Champions League history at 18 years and 34 days, breaking Kylian Mbappé’s record of 18 years and 63 days set in February 2017. Additionally, he became the first player to score against the same team in consecutive games for different clubs, having previously scored against Barcelona while with Antwerp last December.
Yamal, who enjoyed a remarkable year after winning the European Championship with Spain, took 11 Champions League appearances to score his first goal, showcasing another strong performance despite the loss. He now holds the record for the most appearances by a player aged 17 or under in the competition’s history.
Yamal also scored in two consecutive games for the first time with Barcelona and became the second youngest goalscorer in Champions League history at 17 years and 68 days, only behind teammate Ansu Fati, who scored at 17 years and 40 days in December 2019.
