With a reported settlement of $25m to Horizon Sports still fresh in the memory, it would be easy for Rory observers to imagine him never having had a poor day.
But family circumstances were very different in 2005 on the occasion of his breakthrough victory in the West of Ireland Championship.
That's when local bookmakers, Dominic Rooney and Tom Gavin, felt one, good bet would balance the figures.
Totally overlooking the form in stroke-play qualifying, Rooney assured his colleague that all was well, saying: "I gave eights on a young fella named McIlroy."
"Oh sweet Jesus, we're ruined," exploded Gavin, with the look of a man who had just caught his foot in a rat-trap.
Later, Gavin recounted painfully how they had taken a hiding when the 15-year-old went on to win. He further explained that Rory's father, Gerry, had bet €100 each way at odds of 8/1, which delivered a dividend of €1,000 to cover the family's expenses for the trip. From modest beginnings...