“People have been telling me that if I get to the semis I stay at number one so I wanted to do that,” Osaka said. “I was thinking about it while I was playing, which wasn’t a good thing. I play my best when I’m calm and today I wasn’t, so that’s the biggest thing I can learn.”

She heads to Rome next week for her final warm-up before the French Open – but all is clearly not well.

“Today, it was a drama, so much drama in my head. I don’t know what was going on. Normally, I’m able to move on and just concentrate on the next point,” she said.

“I think I was just thinking about too many things. Like, I wanted to win this match so much. Of course I wanted to win the Australian Open and the US Open, but for me, I wanted to win this match more because she beat me before and I just didn’t want to lose twice in a row.”

Things have been turbulent for the 21-year-old Osaka on and off the court ever since Melbourne – and too many of her problems have been self-inflicted.

The announcement – made in a tweet – stunned the tennis world and heaped unwanted pressure and criticism on Osaka.

She lost her first match following the split with Bajin, ironically to the woman he is now coaching, Kristina Mladenovic, in Dubai.

“To be honest, there were some differences,” Bajin said this week, commenting on the split for the first time. “It was her decision. I respect that, no matter what. If there was success or not, whatever the case if she feels like it’s better to go, then that’s her decision.

“We had a great year with seven finals and we had a deal for a year and she didn’t want to continue. It’s OK, I respect her decision. We’re all still friends and we see each other.”

Osaka brought Venus Williams’ former coach Jermaine Jenkins on board but her form has continued to wobble.

The defence of her Indian Wells title, which was the first of her career, ended in the last 16, again by Bencic; she didn’t make it past the round of 32 in Miami, then retired injured before the Stuttgart semis.

She arrived in Madrid clinging onto the her No 1 ranking and, even if she keeps it this week, Halep and Angelique Kerber will be hot on her heels.

“I was thinking about the ranking for a while and I know I tell you guys I don’t really care about rankings, but honestly, I would love to play the French as No 1 because I have never played a grand slam seeded No 1,” Osaka said.

There have been other distractions off court, too. Last month, lawyers representing Osaka and her family filed a motion to dismiss a US$2 million lawsuit from her former childhood coach.

Miami-based coach Christophe Jean claims Osaka’s father, Leonard Francois, made an agreement to pay him 20 per cent of Osaka and her sister Mari’s future earnings in exchange for free coaching.

Osaka has also had to square her down-to-earth attitude – something that has endeared her to the world and made her the new face of tennis – with her new-found fame and fortune.

“I think I got more wins this year [on clay] than I have the entire season last year, so that is definitely a good thing,” Osaka said. “For me, I just wanted to grow comfortable on clay and I think I have. So it is looking good for the French. And, honestly, all I want to do is have fun and I think I’m capturing that spirit again.”