Phil Mickelson has said that the set-up at Merion Golf Club is among the best he has seen for a US Open tournament.
The 42-year-old shot a three-under 67 for his opening round in Pennsylvania, which sees him one shot off leader Luke Donald, who is yet to finish his first round.
Mickelson believes that conditions were as easy as they were going to get during the morning session, but said that the course is still difficult.
"I wish we did not have the delay, because it made it a long day," Mickelson told Sky Sports News.
"The golf course is playing about as easy as it could, but Merion is fighting hard. It's one of the best I've seen for a US Open.
"It's soft but we are having a hard time getting under par."
Mickelson has finished second at the US Open on five occasions.
