Newcastle United claimed their second Old Trafford victory over Manchester United since 1972 to avenge their Carabao Cup final defeat at Wembley.
First-half goals from substitute Miguel Almiron and Lewis Hall, scoring his first goal for the club put the visitors in a comfortable and driving seat at half time.
The goals were followed up by a solo effort from Joe Willock on the hour to give Newcastle their biggest away win over their hosts in 93 years as they cruised into the quarter-finals.
Newcastle will travel to Stamford Bridge to take on fellow Premier League side Chelsea, who beat Blackburn 2-0 in the fourth round.
It was another desperate day for Manchester United and Ten Hag, who have lost eight of their opening 15 games for the first time since the 1962-63 season.
Brazilian midfielder, Casemiro who just returned from injury did not re-appear for the second-half either with Ten Hag evidently unimpressed and replacing him with Amrabat.