The French world number 103 defeated the second seed in three sets on Tuesday to cause one of the upsets of the tournament so far.
"After the draw I wasn't very happy, but I made sure [I was] prepared as well as I could [and] was ready to play my best tennis," Mladenovic told reporters. "When I got on court, I thought, 'I'm at home, be positive.'
"I tried to get my forehand into play and attack her forehand whenever I could and it worked well. I'm really glad I could produce such good tennis in front of all these supporters!"
Mladenovic's reward for beating the world number two is a second-round clash with American Alison Riske.