Stefan Duell has been working for ATP Players for a few years now. Previously he worked with Janko Tipsarevic and he also was part of Team Serbia in Davis Cup.
Stefan was working already with Nole during the pre-season in MonteCarlo and now he is with him in Doha.
— Sports-Physiotherapy (@StefanDuell) diciembre 30, 2015
— Sports-Physiotherapy (@StefanDuell) diciembre 29, 2015