McIlroy had just recorded his third birdie of the day on the seventh to get back to level par for the tournament when he pulled his approach to the par-five eighth – a hole he had eagled on Thursday – into the water.
And after a few seconds’ thought the 25-year-old then hurled the offending long iron into the same stretch of water on his way to recording a six, his third bogey of the day.
It is not the first time McIlroy’s frustrations have got the better of him. At the US Open in 2013 he apologised for throwing one club and leaning so hard on another during the final round that he bent the shaft out of shape.
And that came just months after he walked off the course midway through the second round of the Honda Classic, where he was defending champion, telling reporters he was in “a bad place mentally”.
McIlroy missed the cut in the Honda Classic last week and struggled to an opening 73 at Doral, but looked to be getting back on track when he began his second round with two straight birdies.
However, the four-time major winner then bogeyed the third after driving into the water and three-putted the fourth before the frustrations of the course known as the “Blue Monster” truly took their toll.
Overnight leader JB Holmes could have been forgiven for losing his temper after suffering an early piece of terrible luck as he aimed to build on his brilliant opening 62.
The 32-year-old looked set to carry on where he left off when his approach to the par-five first landed on the front of the green, but the American’s ball began turning to the right as it continued to roll along the putting surface and eventually trickled down a slope and into the water.
Holmes bounced back immediately with a birdie on the second but found more water on the third and this time only had himself to blame, badly miscuing his approach after an excellent drive.
That led to another bogey and meant his four-shot overnight lead had been cut in half until Charley Hoffman, who had covered the back nine in 31 to reach seven under, ran up a quadruple-bogey seven on the fourth.
On nine under par Holmes was three ahead of compatriot Ryan Moore, with former Masters champion Adam Scott and France’s Alexander Levy another shot back.