At a hearing of MEPs in Brussels Ursula von der Leyen took the same line as her predecessor, dashing hopes in Westminster that the EU would use the leadership handover to adjust its stance.
“I think it’s a good deal, but it is your responsibility and your noble task to sort this out,” the German politician told a remain-backing British MEP in the European Parliament.
Responding to another question from an Irish MEP about the backstop she said: “I think the backstop is of utmost importance and we absolutely know how crucial this nonexistent border is for you.
“Having the backstop in the Brexit deal is precious, important and has to be defended.”
The declaration represents the candidate's first comments on Brexit since she was selected for the post.
Ms von der Leyen was nominated by EU leaders to be the political head of the EU's executive branch for the next five years. She faces a vote in the European Parliament to confirm her appointment on Tuesday and is currently in both open and closed consultations with MEPs from across the parliament.
One source familiar with discussions between British MEPs and Ms von der Leyen said the nominee had privately expressed openness to a further extension of Article 50 later this year. The Brexit negotiating period currently runs on October 31; any final decision over an extension would be made by EU leaders at a summit ahead of the deadline.
The centre-right German defence minister's appointment is not a sure thing: while she is likely to get through, she needs to win support from socialists, liberals, and eurosceptics in the parliament to be confirmed.
The parliament's green group, enlarged and emboldened after a good set of results at the European elections in June, have already signalled they would vote against her appointment.
Before being picked as the European Council's nominee for the top job, Ms Von der Leyen had said Brexit was "a loss for everyone" and that events since the referendum had the “burst bubble of hollow promises” woven by Vote Leave.