McIlroy sits at 11-under par through the first two rounds. His 131 is the lowest 36-hole total score in U.S. Open history.
In major championship history, only one player has had a lower 36-hole total score: Nick Faldo (130) at the 1992 Open Championship.
He opened up the tournament bogey free for the first 35 holes before finishing his Friday round with a double-bogey. That was the longest bogey-free streak to start the U.S. Open in the past 20 years.
Thanks to his hot start, McIlroy is the first player in 39 years to lead the U.S. Open at the end of the second round before his 23rd birthday. The last to do that was a 22-year old Lanny Wadkins in 1972 who ended up finishing tied for 25th that year.
Still more people have found themselves comparing McIlroy to Tiger Woods who won his first U.S. Open in 2000. McIlroy's current six-stroke lead matches Woods' record for the largest 36-hole lead at any major ever. He can now set his sights on breaking Woods' tournament record of winning by 15 strokes which he did at Pebble Beach.
All this begs the question: Can anyone catch Rory McIlroy?
History would appear to be on his side. Over the past 40 years, seven other players have held a lead of five or more shots through 36 holes of a major. Six of the seven went on to win.
And McIlroy is the fifth player to head into the third round of a U.S. Open with a lead of at least four strokes. Each of the past three went on to win the event.
Outside of Y.E. Yang at five-under par, no other player is within eight strokes of McIlroy.
Still those players nine shots back (Zach Johnson, Robert Garrigus, Brandt Snedeker, Sergio Garcia and Matt Kuchar)can take solace in the fact that such a comeback would not be unprecedented.
Back in 1975, Lou Graham set a gold standard for comebacks at the U.S. Open. Tom Watson had an 11-stroke edge over Graham but the Nashville, Tennessee native shot 68-73 over the weekend to set up a playoff victory over John Mahaffey for his only career major title.