Graeme McDowell says poor approach play cost him during Thursday's opening round at the US Open, as a four-over-par 74 left him nine shots off the pace.
Dustin Johnson of America and Sweden's Henrik Stenson lead after shooting five-under-par rounds.
"The thing you have to do here is hit your irons well and I didn't do that," said McDowell.
He believes he is capable of getting back into contention by producing "a three, four or five-under-par round" on Friday.
"We can get it going and get back into it," said the 2010 winner.