In purely results terms, there have been few more successful tennis partnerships than Naomi Osaka and Sascha Bajin. In their year spent working together, Osaka climbed from No. 68 to No. 1 in the world and won two of the five grand-slam titles available. Prior to linking up with Bajin, Osaka's best showing at a major was reaching the Wimbledon third round in 2017.

The decision then to split with Bajin just a couple of weeks after winning the Australian Open was a bit like if Arsenal had thought in 2004 that it was time for Arsene Wenger to move along. Or Leicester saying in May 2016: "Thanks for everything, but we're looking for something different now Claudio." Or... well, you get the idea.

Still, at least we could expect platitudes from Osaka about how much she had enjoyed working with Bajin, what a journey it had been, maybe a photo of the two of them on social media? Not quite. Instead Osaka tweeted a terse 26-word statement last Monday: "Hey everyone, I will no longer be working together with Sascha. I thank him for his work and wish him all the best in the future."

Initially the split was dismissed as another example of the leading women's constant striving for improvement. After all the other two reigning grand-slam champions Angelique Kerber and Simona Halep also ended their coaching partnerships after winning majors last year - though it should be noted that Halep's split with Darren Cahill was at his behest not hers. That said, it wasn't long before Halep demonstrated her ruthless streak - confirming on Sunday that she had stopped working with Thierry van Cleemput after a week's trial.