Federer, the five-time champion and looking to end his 10-year wait to add to his total in New York, was beaten by Australia’s world number 55 John Millman 3-6, 7-5, 7-6 (9/7), 7-6 (7/3).
It was 20-time major winner Federer’s first loss against a player outside the top 50 in 41 meetings at the US Open.
He finished with 77 unforced errors and 10 double faults.
It was the world number two’s earliest defeat at the tournament since a fourth round loss to Tommy Robredo in 2013.
Here is how Twitter reacted to his loss:
Federer makes 49% of 1st serves in #USOpen 4R -- 2nd-lowest in his 98 @USOpen matches and 5th-lowest in his 393 Grand Slam matches (47% vs. Agassi 2001 USO 4R).
— ATP Media Info (@ATPMediaInfo) September 4, 2018
RF hits 10 double faults -- his 2nd-most at US Open and tied for 3rd-most at Grand Slams (11 vs. Delpo 2009 USO F).
🇦🇺 men to defeat one of world’s top 2 in a Slam, 1998-18
— Joshua Kay (@js_kay) September 4, 2018
98 🇺🇸 Rafter d Pete
00 🇫🇷 Scud d Pete
00 🇬🇧 Rafter d Andre
00 🇺🇸 Arthurs d Kuerten
01 🇬🇧 Rafter d Andre
03 🇬🇧 Scud d Andre
05 🇦🇺 Hewitt d Roddick
14 🇬🇧 Kyrgios d Nadal
18 🇺🇸 #Millman d #Federer#USOpen
With Roger Federer out, one of the strangest streaks in sports will continue: @rogerfederer and @RafaelNadal have never faced each other at the @usopen.
— Gord Miller (@GMillerTSN) September 4, 2018
To put John Millman's win in perspective:
— Brydon Coverdale (@brydoncoverdale) September 4, 2018
At the age of 29, Roger Federer had won 16 grand slam singles titles.
At the age of 29, Millman hasn't even played in 16 grand slam singles tournaments. #USOpen
Remember this bit: John Millman almost retired because of his injuries. He played anywhere and everywhere to just get on a court. Now he beats Federer in a Slam. What a story #Millmania
— Phil Lutton (@phillutton78) September 4, 2018
This is John Millman's first career win over a top-10 player. He was 0-10 in his career entering his match against Roger Federer. pic.twitter.com/NA6GexKPQT
— ESPN Stats & Info (@ESPNStatsInfo) September 4, 2018
I said at the last Aussie final that “time waits for no one. Except @rogerfederer .” But to be fair, there are NO exceptions. Off nights happen to them all, no matter how great, with increasing frequency as time marches on. And they always make us sad.
— Chris Fowler (@cbfowler) September 4, 2018
No other way to say it: worst match of Federer’s career. By some margin.
— Nick Nemeroff (@NNemeroff) September 4, 2018
Gracious and classy as always.
— US Open Tennis (@usopen) September 4, 2018
Until next time, @rogerfederer...#USOpen pic.twitter.com/zxPLUSbFuD