Defending champion Brooks Koepka (2/11 US PGA Championship outright) is on course to retain his title at the US PGA Championship after a record-breaking start.

The American sits seven clear on 12-under after going round in 65 on the second day at Bethpage Black on Long Island.

He boasts the lowest 36-hole score in major championship history and is unlikely to throw away such a huge advantage.

Koepka’s driving made easy work of the course and he was bogey-free after 27 holes until dropping a shot on the 10th on Friday.

Despite his impressive performance the 29-year-old still managed to find fault in his game.

“This probably sounds bad, but it was a battle,” said Koepka. “I didn’t strike the ball that well. I was leaking a few to the right but I hung in there and battled.

“I think that was probably more impressive than Thursday, not having your ‘A’ game but still being able to shoot a great score.”

Jordan Spieth and Adam Scott (6/5 Top-5 finish) sit in a tie for second on five-under, while Englishman Matt Wallace is a shot back.

Masters champion Tiger Woods failed to make the cut for a sixth time in his past 11 majors after ending Friday on five-over.

Northern Ireland’s Rory McIlroy had an anxious wait to learn if he would make the cut after improving on his opening round score to card 71 on day two.

McIlroy picked up four birdies on his back nine and his three-over, although ruling him out of the running, saw him through.

Odds subject to change