nine holes

They both played their first nine holes in three under par, meaning Yamashita reached the turn three shots clear.

South Africa's Thriston Lawrence, who stormed two shots clear on six under after three successive birdies early in his round, followed that with a run of six bogeys and a double bogey across nine holes as he dropped back to one over.

Masters champion McIlroy had started well and was two under through nine holes, but then unravelled with four bogeys and a double bogey as he posted a four-over 74.

Early this season the 18-year-old from Porter Ranch aced the eighth hole at Knollwood Country Club on his way to shooting four under over nine holes.

McIlroy was at 10 under after nine holes at Sawgrass' iconic Stadium Course but struggled on the second nine, dropping shots at the 12th, 13th and 17th holes as well as missing a presentable birdie chance on the par-five 16th.