(Reuters) - Former world number one Karolina Pliskova has appointed Naomi Osaka’s former coach Sascha Bajin as her new coach for the 2021 season. Pliskova split with coach Daniel Vallverdu earlier this month after her 2020 season came to an end. The 28-year-old posted a photo with Bajin and fitness coach Azuz Simcich on Twitter here on Friday with the caption "Team Pliskova 2021". German coach Bajin led Osaka to back-to-back Grand Slam titles at the U.S. Open in 2018 and the Australian Open the next year. He has also previously worked with 23-times Grand Slam winner Serena Williams. Pliskova lifted her only title of the year at Brisbane in January and was knocked out in the second round of both the U.S. Open and French Open Grand Slams.