Tiger Woods hopes to produce another low round to give himself a chance of winning the US PGA Championship at a "gettable" Bellerive Country Club on Sunday.

Woods shot a four-under 66 for the second round in succession to reach eight under for the tournament, four strokes back from leader Brooks Koepka.

Aiming to win his 15th major championship but first since 2008, the 42-year-old feels the course in Missouri is there for the taking after some heavy rain this week.

Asked what it will take for him to win, Woods said: "Another low round. The golf course is playing soft, it's gettable, you have to make birdies. 

"Look at that front nine. Seemed like everybody was between two and four or five-under par. That's just the nature of the way it's playing right now. 

"It's soft, it's plugging, we're able to hold four irons, five irons, whatever we want, at the flags. Because of that, you got to make birdies.

"I played 29 holes, made — I think I dropped three shots today and two of those were three-putts. I thought I played really clean cards, really clean rounds. 

"And I just wish I could have got myself a couple more shots closer to the lead, especially with 17 the way it's playing, they're moving the tee way up like that. 18's playing pretty short as well."