The 25-year-old is set to be thrusted into the spotlight for the Magpies' last eight Premier League games of the season after second-choice Rob Elliot - who had been deputising for Krul, and deputising well at that - was ruled out for six months with a knee injury.
It is a crushing blow for Newcastle's hopes of survival, with this not being an ideal time to rely on unproven talent as Rafael Benitez's side sit 19th in the table, three points shy of safety with a game in hand.
Nevertheless, Krul is certain that Darlow - who has one Premier League appearance under his belt - has it within him to do "the business" as United look to preserve their top-flight status.
Some Newcastle fans are fearing the worst with Darlow set for a prolonged spell in the side, with a few of them making their feelings on the keeper perfectly clear last night.
Darlow's first test comes in the huge six-pointer away to 17th-placed Norwich City on Saturday, with the Canaries three points above the Magpies.