Erik ten Hag's side took the lead in the first half, through Antony's unstoppable curling effort.
A late brace from substitute Marcus Rashford, however, would seal the win for the Reds in style to continue his fine goalscoring form.
The victory sees us into the two-legged semi-finals of the competition once again, with a place at Wembley at stake.
FIRST HALF - A GOOD START
Ten Hag’s Reds were utterly relentless for the opening 45 minutes in front of the Old Trafford faithful.
Starting on the left, Alejandro Garnacho was electric for United and took no time in introducing himself to the Charlton backline.