Runaway leader Koepka starts round three at Bethpage

Runaway leader Brooks Koepka started his third round at the US PGA Championship with a steady par.

Koepka began the week with a course-record 63 and followed up with a 65 on Friday that left him 12 under par for the tournament, with his 128 strokes marking the lowest 36-hole score in major history.

The American smoked his tee shot off the opening tee at Bethpage Black and followed with a delicate wedge and a missed birdie putt before he rolled in for an opening four.

Playing partner Jordan Spieth also made par at the first as did Adam Scott, and both players were seven shots shy of Koepka.

Dustin Johnson followed a birdie with a bogey and was at four under alongside Jazz Janewattananond and Justin Rose. 

Rory McIlroy signed for a one-under 69 and returned to the clubhouse at two over par for the tournament. The Northern Irishman went three under for his opening nine holes but gave two back on the way home.

Veteran Rich Beem came home in 30 strokes to make the weekend in Long Island but signed for a miserable 12-over-par 82 on Saturday.