LONDON - Manchester United's defence of the League Cup came to a limp end in a 3-0 home defeat by Newcastle on Wednesday as Arsenal were well-beaten 3-1 at West Ham.
Liverpool overcame Bournemouth 2-1 to progress to the quarter-finals, while Chelsea saw off Championship side Blackburn 2-0.
In a repeat of last year's final, which Erik ten Hag's men won 2-0, both managers named much-changed sides at Old Trafford.
But it was Newcastle's strength in depth that showed as United slumped to an eighth defeat in 15 games in all competitions this season -- their worst start to any campaign since 1962/63.
"This is not good enough. We have to take responsibility, I have to take responsibility," said Ten Hag.
"I feel sorry for the fans, it is below our standards and we have to put it right."
Tino Livramento and Lewis Hall have had to wait for their chance to shine since signing for the Magpies but the young full-backs played a huge role as Eddie Howe's side got revenge for defeat at Wembley in February.
Livramento's surging run set up Miguel Almiron to open the scoring on 28 minutes.
Chelsea loanee Hall then volleyed home a brilliant effort from the edge of the box just eight minutes later.
Joe Willock's solo run and stunning finish then drew the sting from any chance of a United fightback on the hour mark.
After eliminating both Manchester City and United, Newcastle's reward is another tough draw away to Chelsea in the last eight.