Rafael Nadal was the defending champion, but he retired in the semifinals against del Potro in a rematch of the previous year's semifinal. Nadal andRoger Federer were in contention for theworld No. 1 singles ranking; Nadal retained the top ranking after Federer lost in the fourth round.
This tournament marked the last major appearance of former world No. 3David Ferrer; he retired from his first round match against Nadal due to injury.[3] This was also the first major since the2017 Wimbledon Championships in which former world No. 1Andy Murray participated, entering with a protected ranking. He lost in the second round toFernando Verdasco.
This marked the first time in the tournament's history that seven former champions competed: Federer, del Potro, Nadal, Djokovic, Murray,Marin Čilić andStan Wawrinka.
Peter Polansky was the first player to qualify for the main draw of all four majors as a lucky loser in a calendar year.[4]