Ukraine’s counter-offensive hopes did not come true, a top security official has conceded.
Kyiv is currently trying to unlock new packages of Western aid, notably in the US.
Mr Danilov believes that at least some military funding will “surely come through”.
The secretary of the National Security and Defence Council has been speaking exclusively to the BBC.
In May, ahead of the counter-offensive, he told us that the coming months presented a “historic opportunity”.
Reflecting on those words now, he said: “In May, every citizen in our country wanted the war to end quickly.
“There were hopes, but they didn’t come true.
“The fact that we have been defending our country for two years is already a big victory.”
Ukrainian forces had hoped to take back swathes of territory gained by Russia in its February 2022 invasion, as well as cutting off Russian supply lines to Crimea.
But lacking air superiority and faced with formidable Russian defences, their efforts appear to have stalled as winter sets in.
Mr Danilov acknowledged they had been over-optimistic.
“People sometimes make mistakes. You cannot be an A-grader all your life,” he said.
He described the current situation on the frontline as “very difficult” and said that old “textbooks” for war – including Nato ones – “should be sent back to the archives”.
“There hasn’t been a war like the one we have in our country – not in the 20th nor the 21st Century,” he argued.
A blame game has crept into public discourse about the degree to which external allies and advisers – or Ukraine’s owned armed forces – are at fault for what happened in recent months.
Mr Danilov refused to be drawn on when a new push to re-take territory could come.
“I can say for sure that we won’t stop,” he said. “We will continue fighting for our freedom, for our independence.”
There has been fresh emphasis in Ukraine on fortifying defensive lines for the winter.
Russia is believed to be encircling the town of Avdiivka and pressing to take full control of nearby Marinka in the Donetsk region.
US aid delay ‘not a tragedy’
Mr Danilov was extremely confident that US defence aid would be approved, even if he wouldn’t put a figure on what Ukraine might hope to get.
A $60bn package is currently embroiled in domestic, partisan politics, with time running out before the Christmas congressional break.
A minority of US Republican lawmakers are sceptical about sending further funds.
“If it happens so that we receive a gift before Christmas, we will be happy with that.”
He added: “But if it will happen a bit later, then it shouldn’t be made into a tragedy.”
Asked whether Ukraine would lose the war if US aid stopped, he refused to entertain the possibility, because “truth is on our side”.
“Will Putin destroy us before humanity’s eyes? https://belakangan.com Will he be killing our children, our women, our elderly men? And will the whole world watch with their eyes closed?
“Then the question should be, in what world do we live?”
Mr Danilov also dismissed reports of tension between President Volodymyr Zelensky and Ukraine’s Commander-in-Chief, Valeriy Zaluzhny.
“I do not confirm that any such things that are being articulated in the media today are real.”