Caroline Wozniacki, 29 and owner of one grand slam title in 15 years, is retiring. Her best friend, Serena Williams, 38 and owner of 23 majors across three decades, is not. What they had to say – to each other and for public consumption – after their almost simultaneous departure from the 2020 Australian Open, painted an indelible picture of a champion in decline.

The Dane does not need tennis anymore. The American still does. Desperately. Both are vulnerable, in contrasting ways.

They had been scripted to meet, play, smile and hug at the net after Williams politely progressed to victory in the fourth round this Sunday before going on to carve her way to the final, where she would lift her 24th slam trophy and take her place alongside Margaret Court, the Australian she respects but does not much like. That’s now a longer shot than it was. Williams has lost four slam finals since winning her 23rd, here three years ago.

Instead of dreaming, she and Wozniacki shared tears after losing in the third round on Friday – Williams to world No 29, Qiang Wang, who took one game off her six months ago at Flushing Meadows; Wozniacki to the artful but erratic Tunisian, Ons Jabeur, who put the British No 1, Johanna Konta, out of this tournament in the first round.

“She came into the locker room afterwards,” Williams said. “We were both kind of bummed about our matches. But it’s not the end of the world. Things go on. Well, I can play better; I don’t know if she’s going to play any better any more. It’s really fresh right now, her retirement.”

And she began to well up again. “She’s had an amazing career. Oh, my God, I’m getting emotional. Oh, my God. I’m going to miss her. I can’t answer Caroline questions, I’m going to be crying. She’s one of my best friends in the world. We will have a great life for the rest of our lives together, but I’m going to miss her out on tour.”

Caroline Wozniacki and her brother Patrik in tears during her retirement ceremony at the Australian Open. Photograph: Francis Malasig/EPA

What disturbed Williams as much as her loss was the way she played against Wang, 10 years her junior with just a couple of titles to her name. Williams described her own performance as, “unprofessional” and, “not cool”.

But she still craves that Court record. “I definitely do believe I can do it, or I wouldn’t be on tour. I don’t play just to have fun. I seem to do well the last two slams of the year. I have won them all several times. Each one is definitely an opportunity for me to go out there and win.

“It’s not even about the slams, it’s about just me playing good tennis, and I didn’t do that today. I’m better than that. I made a lot of errors. I didn’t hit any of those shots in New York or in general in a really long time.”

When Wozniacki followed her – into the same room where Andy Murray broke down in tears before limping away from the tournament in the first round a year ago – she noted, “I was told there are tissues here - just in case I need them. I think I’m cried out, but you never know.”

As seven-slam former champion, Mats Wilander, said on Eurosport, “Serena needs to play more matches. She played fewer than 10 tournaments last year. Maybe the only way back is to practise more and play more matches where you are serving at 15-30 down early on, when there are nerves.”

Or maybe it’s time to wonder if she has gone as far as she can.