ODESSA, Ukraine - World No.22 Dayana Yastremska announced on social media today that Sascha Bajin is to be her new coach entering the 2020 season.

"I am extremely happy, and I am very excited to start our collaboration as it is going to be very interesting and impressive work," wrote the Ukrainian teenager. "I am confident that he can help me in achieving my ambitions. Super excited for the beginning of our preseason preparation and I am confident that everything works out!"

Yastremska was one of 2019's many young breakout stars, winning titles in Hua Hin and Strasbourg and reaching the fourth round of a major for the first time at Wimbledon as she rose from World No.60 at the end of 2018 to her current career high. The 19-year-old also scored wins over Karolina Pliskova, Johanna Konta, Caroline Wozniacki, Garbiñe Muguruza and Aryna Sabalenka, demonstrating the threat of her powerful first-strike tennis to players at the top of the game, and finished the year by qualifying for the Zhuhai Elite Trophy for the first time. Yastremska had parted ways with former coach Olivier Jeunehomme in October.

Read more: 'It's always nice to play against top players' - Yastremska upsets Pliskova to book Wuhan QF spot

Bajin, a former hitting partner for Serena Williams and Victoria Azarenka, went on to win the 2018 WTA Coach of the Year award for his work with two-time major champion Naomi Osaka. Following their split after Osaka's Australian Open triumph this year, the German coached Kristina Mladenovic for the remainder of the season, with the Frenchwoman's ranking rising from World No.67 in February to a year-end placement of World No.40.