world number 1, Serena Williams is out of the Australian Open. (6-4, 3-6, 3-6)

Serena Williams is out of the Australian Open. Her grand slam ambitions, which seemed realistic only a couple of days ago – nailed on, in some estimations, although not her own - lay in tatters on Sunday at the feet of Ana Ivanovic, who had never won more than four games in a single set in their four previous meetings. It was the biggest upset of the tournament, by a distance.

Williams, the world No 1, had to be bullied, almost, into confirming later that she had considered pulling out of the match beforehand with a back injury that has been with her for at least a couple of days. She tried as valiantly to deflect questions about her fitness as she did to heap praise on Ivanovic, the 14th seed who did, indeed, play as well as she has done in a little while. 

Ivanovic recovered from a tentative but energetic start then flourished, irresistible at the end against her stricken foe, to win 4-6, 6-3, 6-3 and go through to the quarter-finals.

Under persistent questioning, Williams conceded, “Yeah, I almost pulled out. I probably should have but I'm such a competitor. I guess the secret is out, but I obviously wasn't hitting the way I normally would hit and wasn't moving the way I normally would move. It wasn't the best.”

What was “it”, exactly? “To be honest, I don't know. I have no idea.”

How long had she had it? “A few days. It's not anything that's life-threatening or anything. I feel like it will get better. I just need a couple days off.”

If Williams had defended that well on court, she might have won.

“It was all Ana today,” she insisted. “I thought she played really well. I made a tremendous amount of errors [31 unforced, against Ivanovic’s 27], shots I missed I normally don't miss, that I haven't missed since the 80s

Guardian.