Naomi Osaka (L) celebrates her victory over Anastasija Sevastova at Melboune Park Photograph:( Reuters )
The Japanese fourth seed defeated Sevastova 4-6 6-3 6-4 and was far from her best as she struggled to hold serve and berated herself regularly during the sun-bathed clash at Rod Laver Arena.
US Open champion Naomi Osaka completed another comeback victory to overhaul 13th seed Anastasija Sevastova 4-6 6-3 6-4 and reach the quarter-finals of the Australian Open on Monday.
The Japanese fourth seed, who had to fight back from a set down against Hsieh Su-Wei in her previous match, was far from her best as she struggled to hold serve and berated herself regularly during the sun-bathed clash at Rod Laver Arena.
She held firm when it counted, however, breaking Sevastova in the seventh game of the decider before sealing the match after one hour and 47 minutes with an imperious forehand down the line.
Osaka will play sixth seed Elina Svitolina for a place in the semi-finals.