Rory Sabbatini made the first birdie of the 97th US PGA Championship when the final major of the year began at Whistling Straits on Thursday.

South African Sabbatini started with a three on the first hole at the testing Wisconsin course, with Ryan Helminen the only one of the first two groups – who teed off at to 6.45am local time – to begin his tournament with a bogey.

All eyes will be on the fit-again world number one and defending champion Rory McIlroy, world number two Jordan Spieth and Open champion Zach Johnson when they tee off at 1.20pm.

Tiger Woods, Keegan Bradley and Martin Kaymer – victor in 2010 when the tournament was last hosted at Whistling Straits – is another eye-catching group, with that trio going out at 8.15am.

Temperatures are expected to hit close to 90 degrees Fahrenheit during the first round, with a 60 per cent chance of thunderstorms.

Gary Woodland was a late withdrawal due to a neck injury, with Carl Pettersson replacing him.