Roger Federer lost to a player ranked outside of the top 50 for the first time at the US Open as Australia's John Millman stunned him to set up a quarter-final against Novak Djokovic.
The 37-year-old Swiss had prioritised winning a sixth title at Flushing Meadows this year, but was far off the pace against the world number 55.
Millman fought back to win 3-6 7-5 7-6 (9-7) 7-6 (7-3) in three hours 38 mins.
Now he meets Djokovic in his first Grand Slam quarter-final on Wednesday.