But the couple announced their split abruptly earlier this month after Raducanu reached her first semi-final in more than a year at the Korea Open.
Tursunov has since revealed that he decided to leave after several "red flags" as he claimed he stuck around after their trial to try and impress her team to no avail.
And the former ATP world number 2 has now explained that he saw the 2021 US Open champion as a "project" who would take a year to 30 months to develop into a top player.
two-and-a-half year project to be sure," Tennis Majors said."This is hard to say and hard for people to understand how it's possible because she is already won the US Open.