Unheralded Australian John Millman pulled off one of the great grand slam upsets by beating Roger Federer in four hugely dramatic sets at the US Open.
Second seed Federer - a five-time champion at Flushing Meadows - was an overwhelming favourite to prevail against the world number 55 and set up a blockbuster quarter-final with Novak Djokovic.
However, the 37-year-old Swiss delivered a strangely lethargic performance on Arthur Ashe Stadium - prompting some pundits to question whether he was 100 per cent fit - and Millman capitalised superbly to earn the biggest win of his career by far.
Federer had never previously lost at the US Open to a player outside the top 50, a record spanning 40 matches, but that streak came to an end as Millman recorded a stunning 3-6 7-5 7-6 (9-7) 7-6 (7-3) triumph.
This performance was definitely one for Federer to swiftly forget as he racked up 77 unforced errors and played a truly bizarre number of drop shots - some good, some awful.
Although Federer won the first three games, he endured an awkward fall after leaping for an early overhead and seemed to be struggling for his usual rhythm from the outset.
After serving successive double faults in the fifth game, Federer missed two routine volleys before wrapping up the first set at the third attempt and he was then forced to save seven break points in a mammoth service game lasting 14 minutes early in the second.
He nevertheless went on to claim the upper hand in set two, but then double-faulted to be broken at the end of another loose game when serving at 5-4.
As Federer's serving went from bad to worse, Millman - who was growing in confidence - immediately broke again to level the match.
The 29-year-old then saved a break point at the start of the third set, which proved a tense affair as both men started to look more comfortable on serve.
A tie-break was required, raising the volume on a court that had often been stunned into near silence, and incredibly it was Millman who prevailed, coming from 3-1 down and saving one set point before taking his second.
Understandably nervous at the start of the contest, Millman now looked inspired and confident of seeing the job through as he greeted winners with no little swagger.
Federer, like any great champion, refused to throw in the towel and showed emotion for the first time after breaking for a 4-2 lead in the fourth.
Yet that break was immediately cancelled out, the animated Millman again demonstrating his character as he got back on level terms.
Federer was on the brink at 5-5, 0-30, but got out of trouble and another breaker soon followed.
Incredibly, Federer then threw in six successive errors after winning the first point - including back-to-back double faults - and Millman converted his third match point to seal an extraordinary victory - his first against a top-10 opponent.
Millman bt Federer  3-6 7-5 7-6 [9-7] 7-6 [7-3]
Millman - 47/28
Federer - 65/77
Millman - 8/1
BREAK POINTS WON
Millman - 3/11
Federer - 3/11
FIRST SERVE PERCENTAGE
Millman - 64
Federer - 49
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Millman - 75/60
Federer - 81/47
Millman - 163
Federer - 154