Rory McIllroy and Shane Lowry carded scores of 69 and 70 after the first round of the men's strokeplay tournament at Tokyo 2020, with Austria's Sepp Straka leading the way on 63.
Play was suspended for two hours with lightning in the air at the Kasumigaseki Country Club, this before Straka set the pace with a bogey-free round that leaves him at eight under.
McIlroy had a bright start with birdies on the third and fourth holes before a bogey soon after on the par-four sixth hole.
A birdie on the 10th put him back at two under, however the gain was dropped at the 12th before a birdie on the par-four 15th saw him card a 69 and a tie for 21st place.
Lowry ended his first round a shot behind his team-mate.
The Offaly man made the turn bogey free including an early birdie on the second.
The back nine saw a shot dropped on the 12th before clawing the loss back with a birdie on the par-three 16th. The 2019 Open champion lies in a tie for 31st.
In second place is Thailand's Jazz Janewattananond, with Belgium's Thomas Pieters and Mexico's Carlos Ortiz tied for third.
Home hero and Masters champion Hideki Matsuyama, who recently recovered from Covid, shot a 69 to be six off the pace but said he felt the lingering effects of his illness as he ran out of gas on the back nine.
Matsuyama had four birdies in his first eight holes before bogeys on nine and 11 stalled him.
Volunteers held up "quiet" signs to patches of vacant grass and British Open champion Collin Morikawa (69) called "fore" somewhat needlessly as he sprayed a shot into trees on the first.
American Morikawa was hardly alone in having to hack his way out of the thick Zoysia grass thriving off the fairways.
