No.5-seed Venus Williams was a finalist in the Australian Open last year.
Last year's finalist Venus Williams is out of the Australian Open, beaten 6-3, 7-5 by Belinda Bencic at Rod Laver Arena.
The turning point in the match came late in the first set when play was stopped to allow for the roof to be closed because of rain at Melbourne Park. After already saving five break points at 4-3, Bencic returned from an almost 30-minute suspension to win six consecutive points to take the first set.
Bencic broke Williams' serve in final game of the match, winning the last four points. She clinched it when Williams, who had slipped on the far side of the court, couldn't get to a ball in the open corner.
Williams was among four American women to lose early on the opening day of the tournament. Bencic warmed up for the Australian Open by combining with Roger Federer to win the Hopman Cup for Switzerland.
Williams lost to her younger sister Serena in last year's Australian final. Serena is not defending her title after giving birth to her first child in September.