One-time grand slam finalist Jo-Wilfried Tsonga dropped out of the ATP World Tour's top 20.
Jo-Wilfried Tsonga slipped to his lowest ranking since storming onto the ATP World Tour scene at the 2008 Australian Open.
Tsonga, preparing to defend his Rogers Cup crown in Montreal starting on Monday, dropped to world number 24 after the latest rankings release due to his tour inactivity since losing in the Wimbledon third round in July.
The Frenchman had only dropped outside the top-20 once in seven years since his run to his maiden major final at Melbourne Park where he - as an unseeded player - lost to then third seed Novak Djokovic in four sets.
Tsonga faces further pain in the rankings if he fails to defend rankings points at the ATP 1000 event in Canada, and will open his week against Croatian 18-year-old Borna Coric in the last match on centre court on Monday.
In other rankings moves, Citi Open champion Kei Nishikori is back at his equal career-high mark of world number four - knocking Stan Wawrinka back to fifth.
John Isner climbed six spots to 12th after his run to the final in Washington, while Dominic Thiem broke into the top-20 for the first time in his career.
Austrian 21-year-old Thiem climbed three places to 18th - the by-product of three titles in 2015, and a semi-final showing on home soil at the Generali Open last week.
Sam Groth (up nine to 53rd) was another top-100 player to reach a career-high mark, as was Romania's Radu Albot (up six to 93rd).