Rory McIlroy dropped five shots in the first three holes of his second round at the US PGA Championship, leaving his hopes of playing the weekend in severe jeopardy.

The former world number one carded an opening 72 at Bethpage Black to be two over and any hopes he had of making ground early on Friday were quickly dashed.

A double bogey at the troublesome 10th hole, where McIlroy started his round, was followed by another dropped shot at the 11th and things worsened at the par-four 12th as the Northern Irishman made a six.

Playing partners Phil Mickelson and Jason Day also toiled on the 11th, the former making double bogey and the latter also dropping a stroke, with the trio taking 16 shots between them.

McIlroy, who won the last of his four majors at the 2014 PGA Championship, was seven over par, four shots off the projected cut line and in need of a swift turnaround in fortunes.

Danny Lee, who was just one shot shy of overnight leader Brooks Koepka after round one, made a miserable start too. He was six over par through nine holes and back to even for the tournament.

Jordan Spieth, looking to complete the career Grand Slam in Long Island this weekend, and Dustin Johnson each improved to two under, leaving them five shots back of Koepka, who was due to start his round at 1:49pm local time.