Millman was adamant he would not be intimidated by Federer, and perhaps was helped by having spent time practising together a few months ago ahead of the grass-court portion of this season.
Still, this was a stunner. Not simply because Federer lost — he entered the day 28-0 at the US Open, and 127-1 in all Grand Slam matches, against foes below No. 50 in the ATP rankings — but how he lost.
Start with this: Federer held two set points while serving for the second at 5-4, 40-15 and did not pull through; he had a set point in the third at 6-5 in the tie-breaker, but again was stymied.
In the fourth set, he went up a break at 4-2, yelling "Come on!" and getting all of those rowdy spectators in their "RF" gear on their feet, prompting the chair umpire to repeatedly plead for silence.
But Federer uncharacteristically got broken right back with a sloppy game, most egregiously when he slapped what should have been an easy putaway into the net.
And then there was his serve.
In the final tie-breaker, he double-faulted twice in a row.
The first obvious signs of trouble for Federer came far earlier, in the second game of the second set. He started that 15-minute struggle by missing 18 of his initial 20 first serves. While he eventually held there, he needed to save seven break points along the way. It was clear that the 37-year-old Federer was not at his best.
Some wonder whether he ever will be again.
Maybe the 75 per cent humidity played a role. Millman's big rips on groundstrokes didn't help matters. As the unforced errors mounted — Federer would finish with 77, nearly three times as many as Millman's 28 — Federer's wife, Mirka, couldn't bear to look, placing her forehead on her hands in the guest box in the stands.
Federer hung his head at a changeover, a little black fan pointed right at his face, but nothing seemed to make him feel like himself.
