It was a savage slapdown that will have stung the most preening President in modern US history.
Philadelphia Mayor Jim Kenney told Donald Trump he needed to "put his big boy pants on" and admit the political reality facing him.
"He needs to acknowledge the fact that he lost and he needs to congratulate the winner, just as Jimmy Carter did, just as George H W Bush did," said Irish-American Kenney.
No chance of that. Trump has spent his entire term of office denouncing his opponents as "losers".
It's psychologically impossible for him to admit that he lost. And lost to 'Sleepy Joe'. Not to some charismatic, high-flying Democrat, but to the man who sat in the Senate for four decades and has nothing of substance to show for it.
"Man is the most vicious of all animals, and life is a series of battles ending in victory or defeat," Trump has written. Accepting failure just isn't in his DNA.
Of course, the psychological needs of one man should not dictate America's political future. The question remains as to how quickly and forcefully the Republican Party will tell him he needs to wise up, and whether he will listen to them.
But this is going to end only one way. "The United States government is perfectly capable of escorting trespassers out of the White House," Biden campaign spokesman Andrew Bates warned on Friday. Trump has long displayed a willingness to take big risks - actions that history will remember.
Yet I struggle to imagine that he will resist exiting office to the point where we have bailiffs at the White House serving an eviction order.
His lawyers are petitioning the Supreme Court to intervene on mail-in ballots. But there seems little chance that even a conservative 6-3 Supreme Court (with three Trump appointees) will overturn the election result.
Trump is shouting long and loud about how the election is being "stolen" from him. But he's put no meat on the bones of his claims. So far there is no actual complaint beyond: "Waaahhh, they cheated!"
Ironically, if a country with a left-wing leader was behaving like Trump and refusing to acknowledge the result of a democratic election, the US would be preparing to overthrow it.
Yet even when he finally departs the White House, Trump will still loom large on the political landscape. He will exhaustively attack a Biden presidency at every twist and turn over the next four years.
The army of young hardline Trumpesque politicians from across the US, who are popping up on our TV screens throughout this election, is evidence that his remains the dominant voice in the Republican Party.
His opponents want to believe that he was just a blip in US politics, and a Biden win will put everything back to the way it was.
But Trump wasn't humiliated in this election. His huge vote means he ain't going away. He won more Hispanic, and even black, votes than any other Republican presidential candidate has done in recent history. He didn't win a second term, but he may end up wielding far more influence than Presidents who do.