An added challenge at the year's final major is provided by the abundance of mosquitoes buzzing across the 7,514-yard links-style layout that hugs the shores of Lake Michigan.
"I've never seen mosquitoes like this, like they have here," former world number one Tiger Woods told reporters on Tuesday.
"I live in Florida and we go out in the evenings and you may get beaten, but here you get eaten alive."
Woods, whose world ranking has plummeted to 278th as he continues to work through the latest swing change of his career after recovering from back surgery, said the fans at Whistling Straits were even more susceptible to the mosquitoes.
