There was no reason to believe that Roger Federer would have any trouble with John Millman in their fourth-round match in Arthur Ashe Stadium on Monday.
Millman, a 29-year-old Australian, was in the fourth round of a Grand Slam event for the first time. Federer had won 20 Grand Slam titles.
Federer was 40-0 at the U.S. Open against players ranked outside the top 50. Millman was ranked 55th.
Millman was 0-10 in his career against top-10 players. Federer was ranked No. 2.
And Federer, a five-time U.S. Open champion, had lost before the quarterfinals only once at the Open in the past 14 years.
Several hours earlier, Novak Djokovic had won his fourth-round match and in the minutes after his victory, he was already being asked about a possible blockbuster quarterfinal matchup against Federer.
But Federer’s play Monday was as sluggish as the air in Ashe Stadium, and it will be Millman facing Djokovic in the quarterfinals after a 3-6, 7-5, 7-6 (7), 7-6 (3) victory. The match ended shortly before 1 a.m. on Tuesday.
“He’s been a hero of mine,” Millman said in an on-court interview. “Today he was definitely not at his best, but I’ll take it.”