SINGAPORE - Reigning Masters champion Sergio Garcia and unheralded American Kurt Kitayama shot matching five-under 66s for a share of the SMBC Singapore Open first round clubhouse lead on Thursday (Jan 18).

Also on five-under are 2010 British Open champion Louis Oosthuizen and Thai Tirawat Kaewsiribandit, but both only completed 16 holes on the Sentosa Golf Club's Serapong course after play was suspended at 5.03pm due to lightning.

World No. 10 Garcia, who teed off on the 10th hole, got off to a slow start and was at one-over after bogeying the par-four 15th. But he then shrugged off the early season rust with a birdie and eagle on the 17th and 18th holes.

"It was a great day but also challenging. I was one-over after (my) seventh hole but it didn't feel like I was playing badly," said the 38-year-old Spaniard, who went on to have a blemish-free second nine.

"Then I hit two great shots in a row on the 17th and 18th, and that settled me a little bit and I could play solid in the back nine and have a great round."

Kitayama, on the other hand, had a busier January after he competed in the Asian Tour qualifying school. He finished third for that event, which ended on Sunday, to earn exempt status for 2018 to play on the Asian Tour.

He did not have a spot in the US$1 million (S$1.3 million) Singapore Open and only got into the field after winning the Monday qualifier.

"I feel really good now, really confident. I started with a birdie (on Hole 3) and just let it roll from there," said the 25-year-old, who fired six birdies to go with one bogey.

"It's great to have a good round early in the tournament, as it proves that I am able to do it."

The remaining half of the 156-player field will return on Friday to complete their opening rounds. The second round is due to start no later than 9am.