for the French Open and entered the tournament as the fifth seed. Following victories against French players Nicolas Mahut and Julien Benneteau, he defeated 31st seed Albert Ramos Viñolas and World N°10 John Isner en route to a quarterfinal clash against World N°4 and frequent rival Marin Cilic. After an intense match (in which he had a heated argument with a fan that supposedly heckled him), Del Potro defeated Cilic in four sets and reached the semifinals, his best performance at Roland Garros since 2009. He then lost to Rafael Nadal in straight sets. His run to the semifinals ensured that, for the first time since February 2014, Delpo would return to his career-best ranking of World No. 4. At Wimbledon, Del Potro defeated Peter Gojowczyk, Feliciano Lopez and Benoit Paire in straight sets to set up a round of 16 clash with Gilles Simon. He went on to beat Simon in 4 sets over two days and in nearly hours to set up another meeting with World No. 1 Rafael Nadal, who defeated him in 5 sets. Del Potro then competed at the Los Cabos Open, where he reached the final but lost to Fabio Fognini. Del Potro was seeded third at the Rogers Cup, but withdrew due to an injury to his left wrist. Nonetheless, due to Alexander Zverev's loss in the quarterfinals, del Potro moved up to a new career-high ranking of World No. 3 as of the week of 13 August. Del Potro was seeded fourth at Cincinnati, defeating Chung Hyeon and Nick Kyrgios before falling to David Goffin in the quarterfinals. Entering the US Open seeded third, del Potro reached the quarterfinals without dropping a set, defeating Donald Young, Denis Kudla, 31st seed Fernando Verdasco, and 20th seed Borna Ćorić. He then faced 11th seed John Isner, defeating him in four sets to reach his second consecutive US Open semifinal, where he faced top seed and defending champion Rafael Nadal in a rematch of the previous year's semifinal. Nadal retired from the match due to a knee injury after del Potro took the first two sets. With this victory, del Potro advanced to his second Grand Slam final, nine years after his 2009 US Open triumph. He was defeated by two-time champion Novak Djokovic, 6–3, 7–6(7–4) 6–3. Del Potro entered the China Open as the top seed. He defeated Albert Ramos Viñolas, Karen Khachanov, Filip