Where Does Billy Horschel's 18 Greens In Regulation Rank?

Considering Billy Horschel's 18-greens in regulation 67 Friday at Merion was played under brutal conditions with hole locations on high spots. It has to rank as one of the great performances in Merion and maybe U.S. Open history.

Bill Fields with the story of the amazing 67 and Billy Horschel's rise in 2013, and some post round comments of note.

"I think some of the pins you can take on, and there are some pins if you do take on and you miss, you miss badly. You pay the price for it," Horschel said. "I was pretty happy if I hit [it] 20, 25 feet. If I made the putt, I was happy with it. And there's some other pins you can go more aggressive and get it a little closer."

And...

Horschel didn't know he had hit every green until he completed the round. He noted that he had achieved the feat "plenty of times in my career," but 15 greens is his best performance in 2013, a season in which he won his first PGA Tour event -- the Zurich Classic in New Orleans in late April.

So, is this on par with David Graham's almost 18 greens?