The 20-year-old University of Ulster student has been musing over the subject online, according to reports in the Herald.
She joked “So yeah, the Masters crystal for the lowest round deserved skittles. What do you fill the US Open Trophy with."
More stories at Rory McIlroy's profile page
Rory McIlroy as a child prodigy chips balls into washing machine- VIDEO
Fame and glory for Rory McIlroy - Irish youngster celebrates stunning US Open win
Holly obviously exceedingly proud of her boyfriend, who is also now $30 million richer, said “My fabulous boyfriend has played flawlessly all week.
On Sunday night she wrote: "Drink up Northern Ireland, he's done us proud. Here's to the sick days tomorrow.
"Wooooooo half 2, champagne flowing. So happy for the curly one."