Kei Nishikori needed three match points to get there but the world No.5 made a winning return to Pat Rafter Arena, seeing off a second-set challenge from Steve Johnson 6-4 7-5 on Pat Rafter Arena.
The No.2 seed at this year’s Brisbane International claimed the win in just under an hour and a half to move into the quarterfinals.
A semi-finalist last year in Brisbane, Nishikori will face an Australian in the last eight, the winner of Wednesday night’s clash between Bernard Tomic and Thanasi Kokkinakis.
The Japanese star said he was looking forward to taking on a local favourite.
“Both players are really up-and-coming players, especially Thanasi,” he said. “We’ve been practising a couple of times and I know he’s very hard to play. It’s going to be an interesting match.”
Earlier on Wednesday, Ukraine’s Alexandr Dolgopolov joined the rout of seeded men by losing to Slovakia’s Martin Klizan.
Klizan fought back from a first set thrashing to become the first man through to the quarter-finals with a 1-6 7-6 (8-6) 7-6 (9-7) victory over seventh seed Dolgopolov.
It means the top four seeds are the only ones left in the men’s draw.
Klizan will face the winner of Wednesday afternoon’s second-round match between Bulgarian star Grigor Dimitrov and France’s Jeremy Chardy.