where he debuted with a victory against Denis Shapovalov. This triumph assured his return to the top 10 of the ATP rankings for the first time since August 2014. Del Potro then defeated Karen Khachanov and David Ferrer en route to the final, where he lost to Roberto Bautista Agut in three sets. At the Australian Open 2018 he lost in the third round against Tomáš Berdych. Despite this, he returned to the top ten ranked world no 9, the first time since August 2014. Del Potro then competed at the Delray Beach Open. However, he lost to eventual champion Frances Tiafoe. He then won the Acapulco Open, defeating Kevin Anderson in straight sets to obtain his 21st title, and his biggest title since 2013 Swiss Indoors. His winning streak would not stop there, however, as he went on to win the BNP Paribas Open, the first Masters 1000 tournament of his career. He received a bye into the second round, where he started his successful run by defeating teenager Alex De Minaur, veteran David Ferrer, compatriot Leonardo Mayer, 31st seed Philipp Kohlschreiber and 32nd seed Milos Raonic en route to the final. There, he faced reigning champion and world No.1 Roger Federer. Del Potro prevailed in three sets despite Federer serving for the match in the decider and holding 3 championship points. This was del Potro's biggest achievement in the ATP Tour after the 2009 US Open. Del Potro continued his impressive run at the Miami Open, again starting from the second round as a seeded player. He defeated Robin Haase, 26th seed Kei Nishikori and 22nd seed Filip Krajinović, before facing off in the quarterfinals against 20th seed Milos Raonic in a rematch of their previous duel. Delpo managed to once again prevail in a grueling match against the Canadian, reaching the semifinals. His streak finally ended as he was defeated by 14th seed and eventual champion John Isner. Delpo would then return to the courts for the clay season, although his first results were unexpectedly lackluster. After starting the Madrid Open with a solid victory against Bosnian Damir Džumhur in the second round, he was upset by qualifier Dušan Lajović in three sets. In his next tournament in Rome, del Potro defeated rising star Stefanos Tsitsipas before retiring against David Goffin in the next round due to a leg injury. The Argentine managed to recover in time