Jason Day and Jordan Spieth have both held golf's number-one ranking in 2016. So it is easy to get the duo mixed up, right?
As the world's top-ranked golfer, a major champion and the winner of eight tournaments since the beginning of 2015 alone, Jason Day is firmly established as one of his sport's leading stars.
Yet it seems not everybody is 100 per cent clear on the identity of the best player in the world.
Day received a surprise on Thursday as he began his defence of the PGA Tour's BMW Championship, with the announcer on the first tee at Crooked Stick seemingly mixing up the tournament's reigning champion with a former number one in Jordan Spieth.
The words, "From Australia, Jordan Day," prompted an amused response from the Australian, who appeared momentarily confused before breaking into a wide smile and acknowledging applause from the crowd.
Pity the poor starter, whose error was swiftly shared on social media.
You could say he had a Day to forget.