Danny Welbeck, a Manchester United academy product, scored a goal against his former team, leading to a mixed reaction from the crowd.
As he was substituted 16 minutes from time, the 9,000 Arsenal supporters in attendance sang his name, while many Manchester United fans booed him.
The negative reaction from the United supporters may have been due to the sale of Welbeck to a rival club last summer.
Alternatively, they may have been upset by Welbeck's celebration after scoring the goal that put Arsenal 2-1 up and secured their place in the FA Cup semi-finals.
