Argentine Emiliano Grillo grabbed the halfway lead as two-time defending champion Brooks Koepka rallied late to stay within striking distance at the midway point of the Dunlop Phoenix golf tournament in Japan.
Grillo shone in gloomy conditions on Friday, shooting a second consecutive four-under 67 at Phoenix Country Club in the southern city of Miyazaki.
The 26-year-old posted an eight-under 134 for the tournament, one stroke better than Japan's Yuki Inamori (68) after 36 holes of the Japan Golf Tour event.
Koepka (68) treaded water for much of the day, before vaulting within three shots of the lead thanks to consecutive birdies on the final three holes.
First round leader Koumei Oda, however, had a day to forget as he plunged five shots behind after a 73.
Leader Grillo, the world No.48, has been in good form recently, tying for second at the PGA Tour CIMB Classic in Kuala Lumpur last month, before tying for 14th at the WGC-HSBC Champions event in Shanghai two weeks later.
Australia's contingent was spearheaded by Lee Won Joon, who racked up eighth birdies in a fluctuating four-under 67 to sit alongside Koepka in a tie for seventh at five under.
Brendan Jones and Brad Kennedy were four and three under respectively while David Bransdon also made the cut at even par for the tournament.
