Muguruza battled with the heat, her health and a fearless opponent before eventually triumphing, 2-6, 6-0, 6-3, in a fraction under two hours here on Monday.
Against a player making her Grand Slam debut, Muguruza's problems were laid bare in an opening set containing 17 unforced errors.
"Well, it happens more in the Grand Slams at the beginning of the rounds because there's a lot of people and sometimes you don't know the opponents," Muguruza said after the match, as quoted by wtatennis.com.
"Today was this sort of case. I went to the court and I didn't really know the opponent. You play and you do your stuff. You kind of see a little bit during the match how she plays, but you cannot know anything before."