Naomi Osaka / Sascha Bajin Split - Why? Wawrinka & Monfils Roll Back Years; Mertens, Opelka Make Their Mark

After a few weeks apart, David Law, Catherine Whitaker and Matt Roberts are back together on this week’s podcast, and the only place to start is Naomi Osaka’s split with Sascha Bajin. 
What could be the reasons behind it ? Should we have seen it coming? And how important is it that she’s prioritising her mental health over her on court success? 
On a similar theme, is Simona Halep on a mission to prove she can win big without a coach? Her trial period with Thierry Van Cleemput was unsuccessful, but she still reached the final in Doha. What makes her conqueror Elise Mertens such a brilliant player? 
Elsewhere, the biggest men’s results from the past fortnight are discussed. How good could New York Open champion Reilly Opelka become? What makes Stan Wawrinka’s return to form so uplifting? Will Gael Monfils kick on from his win in Rotterdam? And why should we be paying close attention to the form of Daniil Medvedev? 
The Tennis Podcast will be weekly throughout 2019 and daily at all the Grand Slam tournaments. It is produced in association with The Telegraph.