Rory McIlroy demonstrates just how extreme the U.S. Open greens are at Oakmont

There are many characteristics that make Oakmont such a legendarily tough course that would attract the masochistic U.S. Open for a record ninth time. Some of those change and evolve over time, or for a particular event like a major championship. But the greens are the constant -- over decades and during regular play or a major. Several players have demonstrated just how lighting-fast things are this week, but Rory McIlroy’s putt above has it all -- the crazy speed and the wild bends and curves on every green.

Most pros this week say only Augusta can really compare to the speed and undulation that they face at this U.S. Open venue. The course is responsible for the invention of the stimpmeter, the relatively simple device that measures green speeds, and it delivers some of the highest readings you can get. This week, the USGA will keep them rolling at about 14 or 14.5 on the stimp, which is up to the edge for tournament play. The club’s longtime pro, Bob Ford, who is retiring after 30-plus years at Oakmont, has said they can get up to 18 on the stimp late in the year with the right conditions. That’s unplayable and like putting on a marble floor.

In addition to the speed, there’s also the wild turns every player will have to tentatively guess on throughout the week. Patrick Rodgers showed just how ridiculous the breaks can get.

And here’s Max Kieffer reinforcing just how easily one little tap can send your ball off wandering many yards away, and often off the green altogether.

So, yes, the U.S. Open is rough, which has characterized the event for so many years. It has been absent in the previous two editions at Chambers Bay and Pinehurst, but now it’s definitely back here at Oakmont. But the greens are still what defines the brutality of this specific test.