Coach Brad Gilbert and 2023 U.S. Open winner Coco Gauff have split.

"Thanks to @CocoGauff and the entire team for an absolutely amazing summer run in 2023 and for 14 months of incredible team effort. Coco, at just 20 years young, your future is incredibly bright, and I wish you nothing but continued success ahead. I'm excited for the next chapter in my Coaching career," Gilbert posted on X Wednesday.

It's unclear whose decision it was to end the coaching partnership.

Considered one of the sport's top coaches and analysts, Gilbert, 63, joined Gauff's team in July 2023 and soon after became her head coach. Gauff reached a career-high ranking of world No. 2 in June under Gilbert's coaching.

However, the relationship has seen some public strain in recent months, with Gauff calling out her coaching team, which also included Jean-Christophe Faurel, after a tough loss to No. 19 seed Emma Navarro at Wimbledon.

Gauff appeared visibly frustrated during the July match, and told reporters afterward, "I don't always ask for advice on the box. Today was one of those rare moments where I felt like I didn't have solutions. I don't want to say I didn't have any, because I think I'm a capable player of coming up with some. I think today mentally there was a lot going on. I felt like I wanted more direction from the box."

After a 14-year pro career with 20 singles titles, Gilbert turned to coaching the likes of Andre Agassi, who described Gilbert as "the greatest coach of all time," Andy Roddick, Andy Murray and more.

--Field Level Media