Heat on as PGA Championship set for cold-blooded shootout

ST. LOUIS, Aug 12 (Reuters) - A glittering leaderboard topped by Brooks Koepka chased by a pack of major winners led by Tiger Woods were poised to turn up the heat on a sweltering Sunday with the final round of the PGA Championship shaping up as cold-blooded shootout.

The temperatures have been high and the scoring low all week at Bellerive Country Club as golfers mercilessly attack the defenseless parkland layout made marshmallow-soft by rain and humidity.

Koepka, twice U.S. Open champion, took a two-shot lead into the final round but muggy weather will not be the only thing making the muscular American feel uncomfortable with some of world's best right on his tail.

Australian Adam Scott, the 2013 Masters champion, sits two back with big-hitting Spaniard Jon Rahm, second-round leader Gary Woodland and Rickie Fowler, widely regarded at the best player yet to claim a major, one stroke further adrift.

But the golfer everyone will be watching lurks four off the pace with Woods back in contention and chasing his first major win in a decade.

"Everyone is going to have to shoot low rounds," Woods said. "It's soft; it's gettable and you can't just go out there and make a bunch of pars. You're going to have to make some birdies."

Joining the 14-times major winner at eight under are American compatriots defending champion and world number two Justin Thomas, 2009 British Open winner Stewart Cink, Australian 2015 PGA champion Jason Day, Irishman Shane Lowry and South African 2011 Masters champion Charl Schwartzel, who matched the record low score in the 100-year history of the PGA Championship with a second-round 63.

"With so many big names, you would expect two or three of them to really make a run, make a push to get off to a good start and challenge me," said Koepka. "Everybody out here is so good and you look at this leaderboard and it's just... they are names that I've grown up watching that everybody else loves to watch play and it should be an exciting day." (Editing by Clare Fallon)