The 19-year-old became the youngest-ever player in the premier league when he came on as a substitute in the third minute of the game.
In the 90th minute, Nwaneri came on as Mikel Arteta's men romped to a three goal victory. William Saliba and Gabriel Jesus were also on target as the team moved back to the top of the table.
Nwaneri was 15 years, 5 months and 23 days old at the time. The player became the youngest ever senior player at the age of 16 years, 5 months and 24 days.
You can watch LaLiga, Bundesliga, MLS, more on the US version of the network.
Nwaneri's appearance marks the latest step in a promising career at the club, where he broke into the under-21 set-up and also represented England at U16 level.
The kid was not born when the stadium opened.