Juvic Pagunsan kicked off his Mitsui Sumitomo Visa Taiheiyo Masters campaign with a decent four-under-par 66 to lie joint-third on Thursday.
The 44-year-old, who's the second-highest ranked Filipino men's golfer in the world, rolled in four birdies in his first 13 holes before giving away a bogey on the 14th at the Taiheiyo Club's Gotemba Course in Shizuoka.
But Pagunsan, who's relentlessly chasing his second JGTO victory since winning the Mizuno Open last year, ensured he stays close to leader Naoto Nakanishi by birdieing the last hole to trail the latter by just two shots.
Reigning JGTO money list winner, Chan Kim of the United States was the next-best placed international after ending the day with a glorious eagle on the par-five 18th to post a 67 and tied for fifth along with local ace Taiga Semikawa and 14-time JGTO winner Kyungtae Kim of South Korea.
Kim's scorecard also comprised three birdies and one bogey.
American Todd Baek, who boasts two-top five finishes in the last two tournaments, opened with a 68 to be tied for 10th while compatriot Jay Choi, South Korean duo Hyunwoo Ryu and Sanghee Lee, and Australia's Brendan Jones, the 2007 winner, were all a further shot back at five shots off the pace.
Pagunsan turned in one of his best performances in recent months as he seemed to have put his inconsistent performance in the first half of the season behind him.
After making only three cuts in the first 11 outings this year, he marked a major improvement by missing the cut only once in the last seven starts, highlighted by a season-best tied-fifth finish at the Panasonic Open in September.
"It has been quite a struggle I must admit, but I know if I keep grinding and persevere, I know everything will fall into place eventually," said Pagunsan.
Nakanishi emerged as the surprise leader with 64 after starting from 10th.
The 34-year-old, who has not won a title yet since turning professional in 2010, carded an eagle and six birdies against two bogeys to finish one ahead of Yujiro Ohori.
Nakanishi believes his major swing overhaul is starting to pay off.
"Ever since I made a major swing modification three weeks ago, I feel like things have started to look up for me," said Nakanishi, who made only three cuts in his first 17 starts of the season.
"The greens were soft today and it was very easy to attack. I hope that the weather will continue to treat us well, so the speed of the greens will even faster.
"But it's also important I must tread with caution."
Leading first round scores:
(Japan unless stated)
64 - Naoto Nakanishi;
65 - Yujiro Ohori;
66 - Hiroshi Iwata, Juvic Pagunsan (Phi);
67 - Chan Kim (US), Taiga Semikawa, Kyungtae Kim (Kor), Akio Sadakata (Jpn), Ryo Katsumata (Jpn);
68 - Yuta Kinoshita, Ryosuke Kinoshita, Todd Baek, Ryo Ishikaa, Ryuta Suzuki (am), Taihei Sato.