However, the Chinese player won five points in a row and held a break point for 3-1 in the third set, before Azarenka peeled off groundstroke winners to hold.
Azarenka broke Li for 4-2 and started producing her most dominant serving of the night. Sneaking to 5-3, the 16th break of the match ended Li’s courageous performance.
Azarenka became only the fourth active player to hold two or more majors, joining Serena Williams with 15, Venus Williams with seven, Maria Sharapova with four and Svetlana Kuznetsova with two.
Meanwhile, US twins Bob and Mike Bryan became the most successful men’s pair in Grand Slam history when they won their 13th doubles title together.
The 34-year-olds beat Dutch pair Robin Haase and Igor Sijsling 6-3, 6-4 to break the record of 12 Grand Slams they had shared with Aussies John Newcombe and Tony Roche.