Jack Sock's 2018 has been a uniquely up and down journey.
The 26-year-old began the year as the top-ranked American male singles player. On the strength of the biggest win of his career at last year's Paris Masters 1000, Sock entered the Australian Open as the eighth-ranked player in the world. He would suffer a disappointing first-round defeat in Melbourne to Yuichi Sugita. It was an ominous sign of losses to come.
Despite a solid showing in Paris this year, which came to an end with his three-set quarterfinal loss to Dominic Thiem on Friday, Sock is set to drop outside of the top 100 when new rankings are released Monday.