Melbourne: Top seed Serena Williams powered into the Australian Open fourth round on Saturday, but only after sister Venus inspired her to shake of a sluggish start against Ukrainian 26th seed Elina Svitolina.
Serena Williams celebrates her win over Elina Svitolina. Pic/AFP
The 18-time Grand Slam champion conceded her first set of the tournament to Svitolina, continuing a run of slow starts, before Venus' hard-fought run into the final 16 at Melbourne Park convinced to her to knuckle down.
The American cruised through 4-6, 6-2, 6-0 when she finally focused, but said she did not know why she continued to zone out as she chases a sixth Australian title with her World No 1 ranking on the line.
"I'm not sure. I need to figure that out," said Williams, who faces dangerous Spanish 24th seed Garbine Muguruza in the fourth round.