World number one Rory McIlroy was frustrated by his putting after an opening round of 72 left him seven shots off the clubhouse lead in the US Open.
McIlroy carded two bogeys and four birdies as he struggled with his technique and the relatively poor standard of the putting surfaces at Chambers Bay.
"They are not the best I have putted on but I should be used to it as the last two tournaments I've played have been just as bad," said McIlroy, who missed the cut in both the BMW PGA Championship at Wentworth and Irish Open at Royal County Down.
"I felt like I played well tee to green and gave myself a lot of looks but did not take advantage of the good shots I was hitting. There were a couple of misreads and a couple of bad strokes in there as well.
"It's hard to pick the line and trust it and then you start making tentative strokes and you are not getting a true roll on the ball. I need to work on that before tomorrow's round and see if I can figure something out."
The good news for McIlroy was that low scores were possible despite the hard and fast conditions, with Ryder Cup team-mate Henrik Stenson and American Dustin Johnson both shooting 65.
"It was set up fair and you see some of the scores that are already in," added McIlroy, who won his first major in the 2011 US Open at Congressional. "Definitely scores in the mid-60s are out there.
"It re-iterates what I was thinking, which is that you can be very aggressive with your tee shots. It's not a typical US Open where you are playing a game of chess."