Angelique Kerber has hired Wim Fissette as her coach in an attempt to recapture a semblance of the form that took her to world number one.
Kerber won the Australian Open and US Open as well as making the Wimbledon final in a glittering 2016, knocking Serena Williams off top spot in the women's game in the process.
The German's win-loss record on the WTA Tour for 2017, however, is a comparatively miserable 29-26, prompting her to ditch her coach of some 12 years, across two spells, Torben Beltz.
"It's been tough but I'm about to start a new chapter in my career, with a new coach," Kerber, now ranked 21st in the world, posted on Twitter.
"Thank you @TorbenBeltz for everything that you've done for me. We share the best memories of my career so far and you've not just been a coach, but also a true friend and that won't change."
Kerber has turned to Fissette, who was most recently behind Johanna Konta's spectacular rise through the rankings, which propelled the Brit to fourth in the world in July.
Fissette and Konta parted company in October after a slump in her game left her in the lower reaches of the top 10.
Kerber added: "The next season is coming soon and I'm very excited to start working with @WimFissette as my new coach.
"It's a new chance and I'm curious to find out what we can achieve together."
Fissette has also worked with the likes of Kim Clijsters, Simona Halep and Victoria Azarenka.