Andrey Rublev hopes his coaching partnership with Marat Safin will last a long time - but it depends if the tennis icon will "enjoy it or suffer".
Russian world number nine Rublev has teamed up with compatriot Safin for the European clay-court swing.
Safin, a former world number one, won the US Open in 2000 and the Australian Open in 2005 before retiring four years later.
The 27-year-old, as Safin did during his playing career, has struggled to keep his emotions in check on court and credited the 45-year-old with helping him with his mental health.