Gabriel, just 15 years old, came off the bench as Michael Carrick's side beat Atletico Madrid 2-1 in a pre-season friendly in what was a mixed performance.
A compilation of the youngster did not impress fans on social media as they mocked the youngster who is only just finding his feet at the club after impressing at an academy level.
The London-born phenom joined the club's ranks aged 11 and is often touted as one of United’s best future talents, leading to him playing regularly for Manchester United's Under-18s 3 years younger than the majority of his teammates.
Bryan Mbeumo said "everything is easy for him" and highlighted his finishing and coaches are constantly in awe of the teenager who is "more than capable" of stepping up to senior football in the future according to Darren Fletcher.
However, Gabriel United cannot legally tie him down to a professional deal yet as he is still 15. As per rules in England, players cannot sign a professional contract until they are 17.
Despite his contract issues, the youngster can play for United in the Premier League during the 2026/27 campaign. This means manager Michael Carrick could hand him a chance and make him one of the youngster players to ever grace the English top flight.
Ethan Nwaneri made his Premier League debut for Arsenal at 15 years and 181 days, becoming the youngest player in Premier League history. Gabriel is currently 15 years and 300 days old.