MELBOURNE, Australia - World No.1 Simona Halep's 6-2, 6-3 defeat of Venus Williams in the third round has set the Romanian up for a much-anticipated fourth-round clash against No.16 seed Serena Williams - and an opportunity to pull off one of the rarest feats in tennis, back-to-back defeats of the legendary Williams sisters.

The 2019 Australian Open will be the 36th tournament (and 13th Grand Slam) at which a player has faced both Serena and Venus, the most accomplished active players on the WTA Tour with 23 and seven Grand Slam titles respectively. It has occurred three times previously in Melbourne: in 2001 (Martina Hingis), 2010 (Li Na) and 2015 (Madison Keys).

    Justine Henin defeated Serena and Venus Williams back-to-back at the 2007 US Open (Getty)

    Only eight players (in nine of those tournaments) have emerged with wins over both sisters, with Kim Clijsters the only player to pull the feat off twice, and only four of those have accomplished this at a Slam. Only five players have gone on to eventually win the tournament.

    Of the 24 occasions on which a player has faced Serena and Venus in back-to-back rounds, only seven have come out with two wins, and only two of those did it at a major - Martina Hingis at the 2001 Australian Open and Justine Henin at the 2007 US Open.

    The full list of players who have defeated both Serena and Venus Williams in the same tournament is:

    • Arantxa Sánchez-Vicario, Sydney 1998. The four-time Grand Slam champion defeated Serena (then a 16-year-old, No.96-ranked qualifier) 6-2, 6-1 in the quarterfinals and Venus 6-1, 6-3 in the final to win the 25th title of her career.
    • Stefanie Graf, Sydney 1999. The 22-time Grand Slam champion defeated Serena 6-2, 3-6, 7-5 in the second round and Venus 4-6, 6-2, 6-4 in the quarterfinals, but fell 6-2, 7-5 to eventual champion Lindsay Davenport in the semifinals.
    • Martina Hingis, Australian Open 2001. The five-time Grand Slam champion defeated Serena 2-6, 6-3, 8-6 in a classic quarterfinal and Venus 6-1, 6-1 in the semifinals, but lost the final 6-4, 6-3 to Jennifer Capriati.
    • Kim Clijsters, WTA Finals 2002. The four-time Grand Slam champion won the biggest title of her career to date when Venus was forced to retire injured trailing 5-0 in their semifinal, before defeating Serena 7-5, 6-3 in the final.
    • Lindsay Davenport, Los Angeles 2004. Injury was also a factor as the three-time Grand Slam champion won her 42nd title: Venus retired trailing 7-5, 2-0 in the semifinal, and then Davenport defeated Serena 6-1, 6-3 in the final.
    • Justine Henin, US Open 2007. The Belgian's seventh and final Grand Slam title was arguably her apotheosis: Henin played two of the most impeccable matches of her career to beat Serena 7-6(3), 6-1 in the quarterfinals and Venus 7-6(2), 6-4 in the semifinals before claiming the trophy with a 6-1, 6-3 final win over Svetlana Kuznetsova.
    • Kim Clijsters, US Open 2009. Playing just her third tournament after returning from maternity leave as an unranked wildcard, the Belgian claimed her second Grand Slam title with a dramatic run at the US Open that included a topsy-turvy 6-0, 0-6, 6-4 defeat of Venus in the fourth round and a 6-4, 7-5 win over defending champion Serena in the semifinals before claiming the trophy with a 7-5, 6-3 victory over Caroline Wozniacki in the final.
    • Jelena Jankovic, Rome 2010. The former World No.1 defeated Venus 6-0, 6-1 in the quarterfinals and then saved a match point to upset top-seeded Serena 4-6, 6-3, 7-6(5) in the semifinals - but unexpectedly lost the final to María José Martínez Sánchez 7-6(5), 7-5.
    • Karolina Pliskova, US Open 2016. The Czech had reached the Top 10 without ever making the second week of a Grand Slam, but she changed that in style in her New York breakthrough, where she defeated Venus 4-6, 6-4, 7-6(3) in a superb fourth round and subsequently Serena 6-2, 7-6(5) in the semifinals, before losing her maiden Grand Slam final 6-3, 4-6, 6-4 to Angelique Kerber.