Former global number one Azarenka, playing her first singles very last in three years, required a clinical timeout after losing the first set to have strapping implemented to her proper calf.
The Belarusian, 29, carried on however become certainly restrained earlier than taking flight when trailing 6-1 three-1.
“i am very happy with this week,” said Spain’s Muguruza, 25.
“it’s a high-quality feeling to come back back and defend a name – it is by no means clean.”
it is -time Grand Slam champion Muguruza’s first identify considering that prevailing in Mexico last yr.
Azarenka final contested a singles final in April 2016, winning both Indian Wells and Miami within two weeks before saying her pregnancy later that 12 months and giving delivery to son Leo in December.
She back to the game competitively the following summer season however has been concerned in a custody battle with her son’s father which has impacted on her tennis.
“it is unfortunate I couldn’t supply my exceptional nowadays, but I tried my hardest,” a tearful Azarenka stated.
“I need to say thanks to my son Leo, who isn’t always with me right here. I would really like him to be right here to share this with me because it’s miles unique.”