Melbourne, Feb 14 (IANS): Twenty three-time Grand Slam champion Serena Williams on Sunday entered the quarter-finals of the Australian Open after fending off a stern challenge from No.7 seed Aryna Sabalenka of Belarus.

Williams overcame Sabalenka 6-4, 2-6, 6-4 in a ferocious fourth-round battle at Rod Laver Arena.

Williams, in her ongoing quest for a 24th major singles title, fired 30 winners, including nine aces, to quell the charge from Sabalenka. Sabalenka had won 18 of her last 19 matches but it is Williams who moves into the last eight in Melbourne for the 13th time in her career.

"It was obviously real important because I didn't want to be out of the tournament, so it felt good to kind of clutch that in the end and get through that," Williams said after the match as per the WTA website.

The American will face either two-time Grand Slam champion Simona Halep or reigning Roland Garros champion Iga Swiatek for a place in the semi-finals.

Earlier in the day, 2019 champion Naomi Osaka saved two match points to beat two-time Grand Slam champion Garbine Muguruza 4-6, 6-4, 7-5, to reach the quarterfinals of the Australian Open for the second time in the past three years.

From 5-3, 15-40 down on serve in the final set, Osaka won four straight games to complete an improbable comeback in an exciting fourth-round contest which lasted one hour and 55 minutes.

She will next face Hsieh Su-wei of Chinese Taipei for a place in last four of the women's singles event.