As a sweltering day turned into a soggy evening at the United States Open, 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.

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Millman was 0-10 in his career against top-10 players. Federer was ranked No. 2.