Serena and Venus Williams will walk the slippery line between sisterly affection and athletic aggression for the 30th time on Friday, fighting for a place in the US Open last 16.

The superstar sisters’ third-round clash is their earliest Grand Slam meeting in 20 years – since Venus beat her younger sister in the second round of the 1998 Australian Open in their first career meeting.

“I never root against her, no matter what,” Serena said.

“So I think that’s the toughest part for me. When you always want someone to win, to have to beat them ... I know it’s the same thing for her.

“When she beats me, she always roots for me as well. I think that’s just the hardest part.”

The possible all-Williams encounter had fans buzzing as soon as the draw was announced, but Venus could barely bring herself to discuss it after securing her passage with a 6-4, 7-5 victory over Camila Giorgi.

Venus’s seven Grand Slam titles include a victory over Serena in the 2001 US Open final. But Serena has gone on to beat her in seven of eight major finals since as she built a 17-12 record over her elder sister.

That included a triumph in the 2017 Australian Open final, where Serena was already pregnant with daughter Olympia.

Venus won the most recent meeting, a third-round clash at Indian Wells in March, but Serena has since gained steam in her post-pregnancy comeback, reaching the final at Wimbledon.

Seeded 17th – nine spots above her world ranking – Serena is trying to avoid her first year since 2011 without a Major title.

If she can pull it off – and the signs improved with the first-round exit of world number one Simona Halep atop her quarter of the draw – Serena will match Australian Margaret Court’s all-time record of 24 Grand Slam singles titles.

It’s not just heightened emotions that make facing Venus so hard, Serena said.

It’s also the challenge of facing a player intimately acquainted with every aspect of her game.

“You have to almost become a different player,” Serena said.

The very factors that make the match-up so daunting for the sisters are what make it so fascinating for fans.

“I’m sure they will hate it, both of them hate this,” former world number one Victoria Azarenka said. “But I think it’s going to be beautiful for tennis.”

Here’s a look at six of the most memorable clashes between the American sisters whose rivalry stretches 20 years.

1998 Australian Open 2nd rd


Nowhere near a classic – it was a described as ‘sub-par’ by one newspaper – but noteworthy as it was the first meeting between the two sisters. Both appeared sporting beads in their hair. Venus, 17 at the time, triumphed 7-6 (7/4), 6-1 which was expected as she was ranked 16 in the world while 16-year-old Serena was down at 53.

2003 Australian Open final


One of the most dramatic finals between the sisters came in the heat of Melbourne, when Serena clinched the last Grand Slam title to elude her with a tension-filled 7-6 (7/4), 3-6, 6-4 victory.

It was only the sixth time a woman had held all four of Grand Slams at the same time, and the first since Steffi Graf in 1994.

Venus made unwanted history as the first woman to lose four straight Grand Slam finals.

2008 Wimbledon final


Venus clinched her fifth Wimbledon title with a 7-5, 6-4 win in one of the few really high-quality clashes between the pair at the All England Club.

Venus defied blustery conditions to become one of only four players to lift the trophy five times or more in the modern era.

She sealed the historic victory when Serena fired a backhand wide, but her celebrations were muted as she hugged her sister at the net.

2009 Dubai semi-final


Venus beat top ranked Serena 6-1, 2-6, 7-6 (7/3) to take a 10-9 lead in the sibling rivalry.

It was Venus’s fifth win in their last seven meetings but Serena earned plenty of plaudits as well for defying the pain of a knee injury that had forced her to retire from a tournament the previous week.

It was only the second time a set had gone all the way to a tie-break in their 19 career meetings to that point.

2009 Wimbledon final

Serena ended Venus’s two-year reign as Wimbledon champion with a 7-6 (7/3), 6-2 victory that secured her a third All England Club crown.

It was the fourth time the sisters had met in a Wimbledon final, with Serena, who now held the Wimbledon, Australian and US Open crowns, winning three of those showpiece showdowns.

She regained the Wimbledon title she won in 2002 and 2003, and shattered five-time champion Venus’s hopes of lifting the trophy for a third successive year.

2017 Australian Open final


Serena secured her seventh Australian Open and an Open-era record 23rd Grand Slam singles title with a 6-4, 6-4 victory, just one shy of Australian Margaret Court’s all-time mark of 24.

It may not have been a classic clash but the enormity of the achievement only became clearer later when it was revealed that Serena was already pregnant with daughter Olympia.

“The last time we met at a Grand Slam, it was two against one,” joked Venus after making the third round of the US Open on Wednesday.

With inputs from AFP