Myles Lewis-Skelly saw red for Arsenal for the second time in a month after he was sent off in their 1-0 defeat by West Ham on Saturday afternoon.
The 18-year-old was adjudged to have with denied a potential goal-scoring opportunity as he fouled Mohammed Kudus on the half-way line.
The West Ham winger dispossessed Lewis-Skelly and had a clear path to goal in front of him, with David Raya way off his line.
Lewis-Skelly made a reckless lunge, initially receiving a yellow card for his transgression.
But, after a short VAR review, the teenager was sent off for the second time in Arsenal's last four Premier League fixtures.