John Robert Isner is an American former professional tennis player. He was ranked as high as world No. 8 in singles and No. 14 in doubles by the Association of Tennis Professionals (ATP).Considered one of the best servers ever to play on the ATP Tour, Isner achieved his career-high singles ranking in July 2018 by virtue of his first Masters 1000 crown at the 2018 Miami Open and a semifinal appearance at the 2018 Wimbledon Championships. He also twice reached the quarterfinals at the US Open in 2011 and 2018, the latter of which helped qualify him for an ATP Finals appearance later that year. At the 2010 Wimbledon Championships, he played the longest professional tennis match in history, requiring five sets and 183 games to defeat Nicolas Mahut in a match which lasted 11 hours and 5 minutes, and was played over the course of three days. Isner holds the record for hitting the ATP's fastest "official" serve ever and third-fastest on record in tennis at 157.2 mph or 253 km/h during his first-round 2016 Davis Cup match. He has the most aces in the history of the ATP Tour, having served 14,470, as of August 31, 2023. Isner retired from professional tennis following the 2023 US Open.

Novak Djokovic defeated the defending champion Rafael Nadal in a rematch of the previous year's final, 6–2, 6–4, 6–7(3–7), 6–1 to win the men's singles tennis title at the 2011 US Open. It was his first US Open title and fourth major title overall. Djokovic saved match points en route to the title, saving two against Roger Federer in the semifinals. This was the second consecutive US Open where Djokovic saved two match points against Federer to reach the final, and the fifth consecutive US Open where Djokovic and Federer played each other. With the loss, Federer failed to win a major in a calendar year for the first time since 2002.