Li Na, the first Chinese singles player to win a Grand Slam title, added another significant first to her collection on Friday by reaching the WTA Championships semi-finals.
Li's trampling 6-2 6-1 win over an ailing Victoria Azarenka carried her to the last four of the tour's flagship tournament for the first time.
Another victory on Saturday, where she will face Petra Kvitova, will make her the first Chinese player to ever climb as high as number three in the world.
From early on there was little doubt that the uncompromising flat hitting of the 31-year-old from Wuhan would earn her revenge for her narrow loss to Azarenka at the Australian Open final in January.
By the sixth game the world number two from Belarus was suffering from a lower back injury, which required three lots of treatment and significantly impaired her movement although Li had already been looking the sharper and more potent attacker.
Azarenka decided against retiring, even though she was often yelling in pain and sometimes close to tears.
"I thought after the first set she would retire," Li said. "It was tough for me to focus all the time. But you never know what will happen.
"The first thing I thought after the first set is that she must retire. If I was feeling very bad I would have retired. If you keep playing you can make an injury worse.
"But when I saw what happened I said to myself 'okay focus, and run for every shot'.
Azarenka explained: "It was a bad movement and, after I served, my back just locked. The physio told me that there was no structural damage but that it would take time to fix it.
"I was a big mess of emotions, but I wanted to do my best for the fans and show respect for my opponent."
These words suggested that Azarenka's worrying decision to carry on, whatever the discomfort, may have been influenced by a large number of previous retirements, and perhaps by the unpopularity she endured with some of the Melbourne crowd at the Australian Open.
There she took a medical time out immediately after missing five match points in her semi-final against Sloane Stephens, and the resulting hostile mood of some of the spectators affected the ambience of Azarenka's final against Li.
Friday's setback ensured that Azarenka, who also lost to Jelena Jankovic, would be eliminated, while the former world number one from Serbia qualified instead.
She has a semi-final on Saturday against world number one Serena Williams, who had already completed three wins on Thursday.
The disappointment almost seemed like a relief to Williams' closest rival.
"I need to look at what's happened and learn more about how to prevent some of these injuries - then I will be ready (for next year) for sure," added Azarenka.
Meanwhile Jankovic lost 6-4 6-4 in her last group match to Sara Errani, the sixth-seeded Italian.
However a more important calculation for Jankovic was almost certainly that of managing her energy levels for a bigger and more important performance - when she takes on Williams, the titleholder, on Saturday.
That is because the one set which Jankovic won in a lengthy encounter with Li Na had guaranteed - irrespective of the result of the last group match - that she would still finish higher in the group table than Errani.
Errani's conquest of Jankovic merely meant that she was able to force Azarenka, originally billed as Williams' closest rival, down into bottom place.
Kvitova, the winner of the 2011 WTA Championships, kept alive her chances of reclaiming the title with a 6-7 (3-7) 6-2 6-3 win over Angelique Kerber which ensured that she qualifies for the semi-finals.
The Czech's success against the German was due to phases of exceptional brilliance off the ground though it was mixed with occasional lapses of concentration which cost her the first set after establishing a lead of 4-1.
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