* Azarenka levels match at one set all
* Chinese suffers ankle injury in second set
The world number one had trouble with her serve in the first set as Li pressured her to take it 6-4 before the Belarusian finally found her range with her groundstrokes in the second set and moved a lot better to race out to a 3-0 lead.
Li broke back, but then suffered a sickening ankle injury after she was forced to change direction when an Azarenka backhand volley deep in the court levelled the score at 30-30 on Li's serve in the fifth game.
The Chinese took a medical timeout to have the ankle heavily strapped but held serve on her return and then got three break points in the next game as both players tightened up and were seemingly unable to hold serve.
With the match on serve at 4-3, Li was broken again by Azarenka who then served out to love in the next game to send it into a decider when a Li forehand sailed wide.
Perhaps weighed down by expectation from the most populous nation in the world and with an estimated 100 million people watching on television in China, Li had a shaky start, serving a double fault on the first point and having her serve broken.
The world number six, however, bounced straight back to the delight of the overwhelmingly pro-Li crowd in Rod Laver Arena and used her powerful forehand to break Azarenka twice to hold a 3-1 lead.
Azarenka then battled back to break to reduce the deficit to 3-2, but was broken again by Li, who was relentlessly attacking the Belarusian's serve.
Azarenka was able to hold for the first time in the eighth game and break in the ninth, but Li broke again on her fourth set point when the Belarusian double faulted to take the first set 6-4.