Serena Williams won World No.1 Simona Halep with a score of 6-1, 4-6, 6-4. Halep after this defeat is in danger of losing No. 1 in the world ranking after 11 consecutive months.
Serena, after a tough fight that reached up to the third set at Rod Laver Arena, qualified for the 13th quarter in the Australian Open quarterfinals.
There she will face Karolina Pliskova to get one step closer to her 24th Grand Slam.