Oakmont's shaved greens are treacherously fast

The average score at the par-70 lay-out almost reached 77 on Friday and some players and pundits voiced their concern that the course was too hard.

The USGA's Jim Hyler said: "We like where we are now and we are going to do all we can to hold it right there.

"It's a hard course. We want it to be a rigorous test, but we want it to be fair. It's our national championship."

But Hyler, the chairman of the United States Golf Association's championship committee, did confirm that Oakmont's treacherous greens had been watered briefly on Friday night and Saturday morning.

The first green, thank God I have spikes on because I think I would have slipped right off the back Tiger Woods

Only four players have carded sub-par rounds this week, two on each day.

Paul Casey shot a 66 in the second round, a feat so outstanding that players stopped putting on the practice green adjacent to the 9th hole to applaud him when he finished.

World number one Tiger Woods, who starts his third round five strokes behind leader Angel Cabrera after shooting a 74 on Friday, felt some of the greens were borderline.

"It's close," he told reporters when asked if he thought the course was getting away from the officials.

"It's right on the edge, I think. The first green, thank God I have spikes on because I think I would have slipped right off the back."

But Oakmont's greens are only part of the problem.

The par-three 8th, for example, is again playing from the back tee and will be 279 yards on Saturday. The 10th is also playing from the back at 462 yards.