Dhaka, July 30 -- Japan's Naomi Osaka, a four-time Grand Slam singles champion, will work with Polish coach Tomasz Wiktorowski on a trial basis after splitting with Patrick Mouratoglou after less than a year together.

Osaka announced the parting with Frenchman Mouratoglou, the former coach of superstar Serena Williams, on social media on Monday before defeating Canadian qualifier Ariana Arseneault 6-4, 6-2 in 76 minutes in a first round match at the WTA Canadian Open in Montreal.

Osaka, ranked 49th, began working in Canada with Wiktorowski, who coached Poland's Agnieszka Radwanska from 2011-2018, helping her reach the Wimbledon final and world number two ranking in July 2012.

Wiktorowski also coached Poland's Iga Swiatek from late 2021...