A pep talk from Roger Federer helped inspire Belinda Bencic to a major upset on the opening day of the Australian Open after she knocked out last year's runner-up, Venus Williams, 6-3, 7-5.

Twelve months after Venus was beaten by her sister Serena in the final, the family will not be represented in the second round of the tournament for the first time since 1997, before Bencic was even born.

The 20-year-old prepared for the year's first grand slam by teaming up with Federer to represent Switzerland at the Hopman Cup, with the pair going on to lift the trophy.

Loading article content

And Bencic had support from the whole Federer family here, with the defending champion offering his advice before the match and congratulating her afterwards while his parents were courtside in Bencic's player box.

She said: "I really admire that before the match in the locker room he's so relaxed, being funny with his team, or even with everyone. Then on court, he's so focused.

"I think that's the main thing I want to learn from him. Even off the court, a normal, humble person, really happy and trying to give advice and help someone like me. I think that makes him pretty special."

After a stellar junior career, Bencic rose quickly through the senior ranks and two years ago was ranked seventh before injury problems struck.

The latest, a wrist injury that required surgery, kept her out for five months and when she returned in September she was ranked 312th.

Not surprisingly, the win over Williams, who she had not taken a set off in four previous meetings, left Bencic beaming from ear to ear.

"It was amazing," she said. "I think the level was great. She beat me four times before so I was really happy I took my chance this time.

"Obviously I'm just happy to be back playing. It was a very, very long time when I was out. I couldn't wait to come back, so it means a lot."

While Bencic had players commiserating over her draw, it proved much worse for her 37-year-old opponent, who made two grand slam finals and one semi-final in 2017.

Williams gave credit to Bencic, saying: "I think she played well. I don't think I played a bad match. She just played above and beyond."

The result compounded an already bad day for the American women, with US Open champion Sloane Stephens continuing her losing run.

Stephens has not won a match since her stunning triumph in New York and a 2-6, 7-6 (7/4), 6-2 defeat by Zhang Shuai made it eight losses in a row.

But Stephens believes the negativity about her form is unfair.

"I won a grand slam, I'm going through a tough time," she said. "Who cares? No one cares about my life. I'm just having fun. I'm enjoying it.

"There's too much emphasis on the bad things that happen after something really great happens. That kind of sucks."

All four women in the semi-finals at Flushing Meadows were from the US but three of them are already out, with 10th seed Coco Vandeweghe beaten 7-6, (7/4), 6-2 by Hungary's Timea Babos.

French Open champion Jelena Ostapenko has bucked the trend by showing great form after her maiden slam triumph and she eased into round two with a 6-1, 6-4 victory over Francesca Schiavone.

Dark horse Julia Goerges won her 15th straight match 6-4, 6-4 over Sofia Kenin but former finalist Dominika Cibulkova was beaten 6-2, 6-2 by Kaia Kanepi.

There were confident starts for two of the title favourites in the evening session.

Second seed Caroline Wozniacki eased past in-form Romanian Mihaela Buzarnescu 6-2, 6-3 while fourth seed Elina Svitolina was a 6-,3 6-2 winner against Ivana Jorovic.

The youngest woman in the draw, meanwhile, continued her brilliant start to her grand slam career.

Fifteen-year-old Marta Kostyuk was given a wild card into qualifying after winning the junior title last year and won three matches to reach the main draw.

In her first ever tour level match, the Ukrainian shone in a 6-2, 6-2 victory over 25th seed Peng Shuai.