US Open 2015: Rory McIlroy rues missed chances at Chambers Bay

Rory McIlroy is unable to overcome his putting struggles in the US Open as a level-par 70 in the third round leaves him eight shots off the pace.

"I felt like it could have been a 64 or 65 today so to shoot 70 is disappointing," said the world number one.

"I'm in a bad habit of turning good scores into average ones."

Jason Day, Dustin Johnson, Jordan Spieth and Branden Grace are leading on four under par with Ireland's Shane Lowry sharing fifth place on one under.