Ryo Ishikawa had a woeful opening round at the Dunlop Phoenix on Thursday with seven bogeys for a 4-over 75 to stand in 58th place.
Ishikawa, out for his second straight win following victory in the Taiheiyo Masters last weekend, bogeyed four holes on the front nine at Phoenix Country Club.
The 19-year-old Ishikawa is already nine shots off the pace of Hideto Tanihara, who lit up the course with five birdies on a bogey-free afternoon.
"It will be difficult, but I've got to try to make up three shots a day," Ishikawa said. "I know what I did wrong today, and I think managed to make a few adjustments.
"It's a tough course, but that means it's tough for everyone else, too. If this were an easy course, I wouldn't be able to close the gap even with one great round because everyone would be playing well.
"But I still have a chance because of the difficulties here," he said.
Yuta Ikeda and Tetsuji Hiratsuka trailed Tanihara by one stroke to share second, while JGTO money leader Kim Kyung Tae launched his assault on the title with a 68 in a four-way tie for third.