However, the former world number one managed to compose herself to defeat her Austrian opponent, dropping only five games in the process.
After her victory in Melbourne, Williams also revealed that she is feeling in good shape.
"I think I was a wee bit tight out there today. I always get a little nervous in my first-round matches. I definitely didn't play any way that I practised. So hopefully I can get better," Williams told reporters.
"Physically I felt fine. I was definitely moving better than, you know, I suspected.
"I still think I can move better, though, and just get that confidence. It would be great."
Williams will now face Barbora Zahlavova Strycova in the next round.