At the age of 15 years and 181 days, Nwaneri became the youngest ever player in the English premier league.
The schoolboy was sent on by Mikel Arteta in the last moments of the game.
The travelling fans sang "He's going to school in the morning" when Nwaneri appeared.
The France defender climbed high to head the corner in off the post, setting the stage for a sixth victory in seven top-flight games this season.
It was 2-0 in the first half an hour as Jesus headed Granit Xhaka's chip past David Raya.
In his first start in the league since joining from Porto, the Portuguese player scored a 25 yard goal.
Ivan Toney, who has been called up by England for the first time, struggled for service as the Bees were held to a nil-all draw.
After Manchester City and Spurs won on Saturday, the top of the table became a three-way race.
The win puts the club on 18 points, one more than their nearest rivals, and they will play Spurs in the north London derby on October 1st.
The opening day of the 2021-22 campaign saw a 2-0 defeat for the Gunners, who were bullied in the corresponding fixture a year ago.
A lot has changed since then and this is a very different team.
All of the attention was on how they would respond against a side that embarrassed United five weeks ago.
They dominated from beginning to end despite the absence of Martin Odegaard.
Gabriel Martinelli once again put in an eye-catching shift, Saliba was strong at the back while Saka, who also teed-up Vieira, finished with two assists as the north London club swept to a third clean-sheet away win of the season.
The margin of victory could have been more but for two fine saves by Raya to keep out Jesus and Saka.
In the last two years, they haven't played in the European club competition.
There is still a long way to go, but signs look promising for Arteta as the team continues to build on a strong start and give their supporters hope they can qualify for European club football's most prestigious competition
There hasn't been a sign of second-season syndrome after the wins over Manchester United and Leeds.
They went into the international break in the top half of the table, despite being distinctly second best against the north London club.
It has been 18 months since Toney became the first Bees player to be called up by England since 1939.
After a free-kick, Toney went closest to scoring for the hosts but they were unable to find the back of the net.
This was a day to forget for the Bees, who have come a long way in a short period of time.
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