Istanbul: Li Na, the first Chinese player to win a Grand Slam singles title, added another famous first to her collection when she reached the semi-finals of the WTA Championships with a 6-2, 6-1 rout of an ailing Victoria Azarenka on Friday.
It was the first time Li had qualified from the group stage of the tour`s flagship tournament, and there was rarely any doubt that she would do so with a success which avenged her narrow defeat to the Belarusian at the Australian Open final in January.
Azarenka suffered a lower back injury in the sixth game and required three lots of treatment and significantly impaired her movement.
However, Li had already been looking the sharper and more potent attacker, and had become the favourite to deliver her third win in three encounters and finish top of her group.
"I thought after the first set she would retire," Li said of the injured Azarenka.
"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`."
The result also ensured that Azarenka was eliminated and that Jelena Jankovic, the former world number one from Serbia, qualifies from the White Group in second place.
Jankovic will face Serena Williams in Saturday`s semi-finals while Li will meet Petra Kvitova, the 2011 champion.
Kvitova made the semi-finals with a 6-7 (3/7), 6-2, 6-3 win over Angelique Kerber of Germany.
The Czech`s success against the German gained her a second win in the Red Group.
Kvitova`s brilliance off the ground was mixed with occasional lapses of concentration which cost her the first set after establishing a lead of 4-1.
However, she was both forceful and focussed while dominating the second set, and snatched an early break in the decider which transformed the mood of the match.
Kvitova`s group was topped by Williams, who completed her three wins on Thursday.
Jankovic became certain of finishing runner-up in the White Group -- irrespective of the result of her final group match against Sara Errani -- as a consequence of Li`s victory over Azarenka.