But the biggest shock of day one came when 20-year-old Swiss hitter Belinda Bencic dispatched last year's Australian Open finalist Venus Williams in straight sets, making it the first time since 1997 neither Williams sisters would make an appearance in the second round of the tournament.

The disappointed 7-time Grand Slam winner told Xinhua after the match, Bencic played "above and beyond."

"I don't think I played a bad match," Williams said, "Maybe I had a few too many unforced errors. I think she just played well."

Another high profile exit came when China's Zhang Shuai fought back from a set down to defeat 2017 U.S. open winner Sloane Stephens.

But the drama wasn't finished there as another American superstar crashed out of the tournament, when Timea Babos from Hungary finished CoCo Vandeweghe in straight sets.

The match featured a truly bizarre moment when Vandeweghe was issued a time violation after the fiery competitor waited "too long" for courtside banana snack at the end of the first set.

Former world number one Sam Stosur also failed to make her way out of the first round.

However Caroline Wozniacki, Elina Svitolina, Jelena Ostapenko and Julia Gorges all made light work of their opening matches and China's Duan Yingying blasted her way past Colombian Mariana Duque Marino in straight sets 6-0, 6-1.