FIfth seed Kei Nishikori battled through the heat to progress to the quarterfinals with a hard-fought 6-3, 6-3 victory over Spanish veteran Tommy Robredo.
In warm Brisbane conditions, the world No.19 utilised his superior court coverage and pace-of-shot to run the 31-year-old Robredo ragged.
Nishikori was able to apply constant pressure on the Robredo serve, converting three of 11 break point opportunities.
It is the second time the 23-year-old Nishikori has progressed to the quarterfinals after also reaching the final eight in 2009.
His opponent will be either fourth seed Alexandr Dolgopolov or Finland’s Jarkko Nieminen.