DeChambeau revealed afterwards that McIlroy hadn't spoken to him at all during their 18 holes together in a blunt post-round interview at Augusta National.
DeChambeau hit reverse as he went out in Sunday's final group with McIlroy, initially overturning his rival's lead before spluttering to -7 for the tournament and a tied fifth finish.
Bryson DeChambeau, the big-hitting LIV Golf star, teed it up alongside McIlroy with two set to battle it out for the Green Jacket over the undulating fairways of Augusta National Sunday.
OLIVER HOLT AT AUGUSTA: It was not simply staring down DeChambeau that made McIlroy's triumph one of the greatest and most courageous victories in the history of golf.
The Northern Irishman goes into the final day with a two-shot lead over his American rival, in a rematch of the 2024 US Open that saw DeChambeau come from behind to beat him.
Watch as Bryson DeChambeau holes "impossible" putt to make sure Rory McIlroy will only have a two-shot lead going into the final round of the Masters at Augusta.