Second-seeded Serena Williams of the United States defeated Czech tennis player Barbora Strycova 7-5, 6-4 in an hour and 46 minutes to enter the quarter-finals of the Australian Open here on Monday.
"I feel like it was really good for me to win on probably not my best day, which is always good," said the US player after the match, reports Efe.
"Because sometimes you rely on one shot and if it goes off, and then, like, what happens now?"
The defeat of Germany's Angelique Kerber in the previous round to US player Coco Vandeweghe has opened the possibility of Serena winning the championship, as well as regaining the World No.1 ranking which she lost to Kerber in September after 186 consecutive weeks on top of the rankings.
Serena will now face British player Johanna Kota, who eliminated Russia's Ekaterina Makarova.