Meanwhile, what an astonishing Wimbledon this has been for Zhang, and how fitting that this key match should have been against Halep.

The Chinese captured her maiden Grand Slam match win as a qualifier at the Australian Open in 2016, having lost all 14 of her previous main draw matches in a wretched run stretching back to 2008. The player she defeated to snap that losing streak was Halep, then the world No.2, and Zhang went on to reach the quarter-finals that year in Melbourne. But it has been a chequered path for her since.

Even so, last year she announced to family and friends: “I am going to win a Grand Slam title in 2019” – and so she has, capturing the doubles with Samantha Stosur at the Australian Open.

Coming in to this singles quarter-final, her impressive roll call of scalps had already included ex-top five player (and a good mate) Caroline Garcia, the former US Open semi-finalist Yanina Wickmayer, the former world No.1 Caroline Wozniacki and the fast-rising Ukrainian teenager Dayana Yastremska.

As soon as the match began, it was evident that Zhang’s success here was no fluke. The work rate, the intensity, the quality – it was all here from both players, but Zhang was out of the gate like a rocket, breaking at once in a display of utter confidence and composure.

Pushing the ball as deep and as wide as the limits would allow, she was nervelessly focused as she dictated the play. Amid rallies routinely over ten strokes, she leapt out to a 4-1 advantage. Four times already this year Halep had lost to players ranked outside the top 30. Would this be number five?

But there are times in tennis when one mini-chapter or another has Big Game written all over it, and game six in the first set was that mini-chapter. It was ten minutes on which so much hinged.

Four times Zhang had break point for 5-1, to serve for the first set; but all Halep’s fighting qualities saw her hang on. It gave her a toehold on the cliff-face, and from there the Romanian hauled herself onward. She began to have a say in the shape of the rallies, although it was draining toil and her audible frustration was evident more than once.