Mahan eventually rallied with three straight birdies on the back nine for a comfortable two-shot win in the FedEx Cup playoff opener.
Maybe too comfortable.
While posing with the The Barclays trophy alongside a fan, Mahan gripped the crystal chalice only to discover he had broken it in two, watching as its bowl became separated from its base.
The incident sparked a round of laughter from David Finn, a popular fan in the area Mahan was posing with, who is in a wheelchair with a disorder affecting his limbs and leaving him unable to speak.
"David did it," Mahan promptly joked, according to The Newark Star-Ledger.
But Mahan wasn't so willing to discuss it afterward.
"I have no idea what you're talking about," Mahan said while smiling in the event's media tent, The Star-Ledger reported.
But the trophy can be repaired or replaced.
And the victory was one Mahan won't soon forget.
"There's really never a bad time to play good golf," said Mahan, who earned $1.44 million, moved to No. 1 in the FedEx Cup standings and assured himself of being among the top five players at the Tour Championship in three weeks with the best shot at capturing a $10 million bonus.
"And this is a really, really good time to play good golf."
Information from The Associated Press was used in this report.