US Open Leaderboard 2012: Latest Updates on Top Trios

The first round of the US Open is well underway, and many of the event's top pairings have already finished their first 18 holes of golf.

It's certainly been a mixed bag of successes and failures for many of golf's best, as the field has struggled to hit low scores, confirming the Open's status as the toughest major in the sport. But, with all the chaos of the opening round, how did the sport's best pairings fare? Has anyone fallen out of contention already?

Let's take a look at a few of the most widely anticipated pairings in the Open and how they fared in the first round at the Olympic Club. 

Tiger Woods, Phil Mickelson, Bubba Watson

This was the pairing golf fans have been the most excited about, for obvious reasons. But the most prominent pairing in the tournament didn't have the kind of universal success golf fans were hoping for on Thursday. 

We'll start with the good news. Tiger Woods seemed to find his groove once again in the first round at the Olympic Club, holing birdies on his fourth, fifth and 17th holes while hitting two bogies to finish one under par and tied for fourth at the end of his day.

Woods' putter wasn't great, and he missed some make-able putts on the day. Woods is very much in contention, and if he can sort out his putting, he could run roughshod over this field. 

However, that's pretty much where the good news ends for this prestigious group. Phil Mickelson imploded early in the round, bogeying seven holes en route to a six-over 76.

Lefty played all day in trouble, scrambling to hit the green as his scatter-shot accuracy off the tee cost him once again. He's currently 10 strokes back of the lead, and unless he can find his groove on Friday, there's a good chance he could miss the cut. 

If that's not bad enough, Watson failed to re-capture the mojo he had at the Masters, showing serious rust from the lengthy hiatus he'd taken after Augusta.

He shot an eight-over 78, and much like Phil, he struggled with the Olympic Club's short, narrow fairways. He was under par on only one hole, and immediately cancelled out the birdie on his 17th hole with a double bogey on his 18th. At this point, Bubba's out of contention barring a miraculous rally, and I wouldn't be shocked to see him miss the cut. 

Martin Kaymer, Hunter Mahan, Justin Rose

It's been a slow day through the early holes for this trio. Mahan and Kaymer are both at even par through six holes, putting them four strokes off the lead, while Rose sits one over par through the same number of holes.

Given the high scores that have plagued many of the sport's best on Thursday, if these three can continue to grind out pars with the occasional birdie, they should be in good shape heading into Friday. 

Luke Donald, Rory McIlroy, Lee Westwood

While this trio of Brits is just four holes into their first round at this stage, things have not gotten off to a good start for any of them. Westwood hit the ground stumbling, double bogeying his first hole of the day, then following that with another bogey on the third. He currently sits three-over through five holes and is going to need to pull himself together in a hurry if he hopes to contend in this one. 

Meanwhile, Donald's tournament is off to an equally lousy start. Through his first five holes of the day, Westwood has three bogeys and two pars, and he sits three over through five.

McIlroy isn't nearly as bad as the other two, sitting one over through his first five holes, but he's going to need to rally a bit to get back into contention on the day. Given his recent slump, it's tough to see McIlroy putting together a strong run at the Olympic Club.