Shane Lowry has admitted that the rules fiasco during the US Open final round at Oakmount affected his play more than it had initially been reported.
The world number 25 held a four-shot lead going into the final round before he shot a closing 76 to finish three shots behind eventual winner Dustin Johnson.
Uncertainty over the possibility of Johnson receiving a one-shot penalty for causing his ball to move on the fifth played a significant role on the Irishman's mindset during the final stretch.
"I did my interviews afterwards and I said it didn't affect me at all," Lowry said at the WGC-Bridgestone Invitational press conference. "But when I look back on it, it did.
"The few days after the U.S. Open were quite tough. Anytime I was on my own, I was thinking what if I had done this, or if this would have happened, and I was driving myself mad.
"He might have got away with that penalty shot if he really needed to. I mean, it would have been interesting to see if the two of us had been tied, or I would have won by one, whether Dustin would have got penalized that shot or not," he said. "I think we might have had a different scenario then."
Lowry has been paired with last year's runner-up Bubba Watson and Japan's Hideki Matsuyama for the first two rounds of the WGC-Bridgestone Invitational at Firestone Country Club, with Johnson alongside the man he succeeded as US Open champion, Jordan Spieth, and 2013 winner Justin Rose.