Naomi Osaka splits with coach Jermaine Jenkins
Two-time Grand Slam champion Naomi Osaka has sacked her second coach in seven months, splitting with Jermaine Jenkins in the wake of her disappointing US Open title defence.
Jenkins, a long-time hitting partner of Venus Williams, replaced Sascha Bajin in February, weeks after Osaka's victory at the Australian Open.
"I'm super grateful for the time we spent together and the things I learned on and off the court but I feel like now is an appropriate time for change," the Japanese 21-year-old wrote on Twitter.
"Appreciate you, forever warmed by you ... Thank you for everything, it was a blast."
Top seed at Flushing Meadows, former world No 1 Osaka struggled with a knee problem before being upset by 13th seed Belinda Bencic in straight sets in the fourth round.
It continued a difficult season for the power hitter since her second Grand Slam title at Melbourne Park, with early exits at the French Open and Wimbledon.
Osaka fell to fourth in the WTA rankings after an early exit at the US Open
The Australian Open win made her Asia's first world No 1 and the first player of any nation to claim the first two Grand Slam titles back-to-back since Jennifer Capriati in 2001.
Her early exit from New York has seen her ranking slide to four behind Ashleigh Barty, Karolina Pliskova and Elina Svitolina.