Live updates with Tiger Woods

8:21 p.m. - Play ends for the day, good news for Tiger

Play has ended for the day, and that gives Woods some much needed rest. His left arm is becoming a problem.

Woods landed in the rough on the 11th hole. After his shot (which was well short of the green) he bent over in pain, flexing his left elbow. The injury appears to be to his elbow, and the ESPN's commentators agree. The issue is most exaggerated when he's in the rough, which can put extra strain on his arms. He finishes two-over through 11 holes on the day. - Zach Helfand

8:12 p.m. – A bleeping miss for Tiger

Though his tee shot was bad enough to elicit a muttered four-letter expletive that starts with "f,"
Woods recovered to give himself another makeable birdie putt.

The putting woes continued. Woods' attempt missed by a fraction, and he settled for par. If anything deserves Woods' swearing, it's not his play off the tee. It's the strokes he's leaving on the green.  -Zach Helfand

7:57 p.m. – Woods sputters through first half of opening round

Woods three-putted on nine to finish the front half of the course at plus-two. Woods just missed a long birdie putt and then pushed an easy par putt wide for a bogey.

Woods' missed birdie putts on the last two holes have drawn some interesting explanations from the commentators on the USGA's online live feed. One hypothesized that the chirping of a red-eyed Vireo, a small song bird, interrupted Woods' focus while putting on the eighth green. Woods' birdie putt on the ninth was "a hair frisky." - Zach Helfand

7:42 p.m. - Woods pars a pair of holes after birdie

A hole after sinking a 60-foot putt, Tiger Woods came up short and was forced to settle for par on the seventh. His 15-foot birdie put fell just to the left of the cup.

He opened the eighth with a strong drive onto the middle of the fairway. Woods then sailed his approach shot onto the green and set up a short birdie putt but missed to the left. He finished the putt and is shooting one-over through eight.

Adam Scott birdied the hole and Rory McIlroy shot one over par-4. Scott is two under for the round and McIlroy is one-under. – Matt Breen

7:20 p.m. - Woods sinks 60-foot put

Tiger Woods' approach on the sixth hole looked to be the safe play. He reached the green in regulation, but he didn't attacks the pin, leaving himself a very lengthy putt. It was a good set up for a par.

But though Woods didn't attack on the approach, he did with the putt. He putt a lot of speed on the attempt, but it found the center of the cup. He converted the birdie from about 60 feet to improve to one-over, and he did it on the third hardest hole of the course. Just four other players have birdied on the sixth. - Zach Helfand

6:55 Tiger makes bogey on 5th as play resumes

Tiger Woods finished off a tough bogey on the 5th hole after play began again, less than an hour after it was suspended with severe rains rushing through the area. Woods is now 2-over-par, five shots behind the leaders. -- Gary Potosky

6:13 p.m. - Play suspended much to the relief of Woods

The horn suspending play blew at about 6:10 p.m., and that was probably good for Woods. Woods' difficult start continued on five, the hardest hole on the course. With his ball on the apron behind the green, Woods lined up a chip when someone yelled during his backswing. Woods was able to hold up, and he took a moment to gather himself.

He stepped up again but his chip was well short of the hole. He again misjudged the sloping green — perhaps the toughest at Merion — and his par save was again well short. He still had a difficult putt left, and Woods left the green with a relieved smile after shaking hands with Scott and McIlroy.

Scott and McIlroy were able to finish the hole. Scott picked up his first bogey of the day to drop to one-under. McIlroy shot a par and is also minus-one. -Zach Helfand

6:11 p.m. - Woods appears in pain

On two separate occasions, Woods has winced in pain after hitting a shot. After hitting his second shot from the first cut of rough on the fifth hole, woods grimaced, then flexed his left hand and bent his elbow. Woods then shook his arm and again flexed his left hand. He did the same on the first hole. -Zach Helfand

5:52 p.m. - Woods pars fourth hole

Woods has found his par. He laid up on the par-five fourth, but his third shot left him a lot of work on the green. His birdie attempt had a promising line but didn't have enough speed, and he tapped in for par. He remains at plus-one.  

One gambled, one played it safe, but both Rory McIlroy and Adam Scott left the fourth hole with a birdie.

Scott's attempt to reach the par-five hole in two shots left him in a greenside bunker. But an impressive out left him an easy birdie putt. He is already two strokes under par.

McIlroy laid up and also sank a birdie putt to improve to one-under. --Zach Helfand

-Zach Helfand

5:33 p.m. – Another bogey for Woods

Woods is still searching for a par. After going bogey-birdie on his first two holes, Woods settled for another bogey in the third hole.

His par putt curled just around the hole from about 20 feet back, and he's now back to one-over. -Zach Helfand

5:22 p.m. - Woods back to even par

After three-putting and ending up with a bogey on the first hole, Tiger Woods atoned for it on the second.

He sank a birdie putt to get back to even par. He's on the tee first at the Par-3 third, a driveable hole.

Adam Scott and Rory McIllroy both shot an even par five. All three players are even par through two holes.

--Tim McManus

4:58 p.m - Woods tees off

The headline act approached the tee and the crowd came to hush at Merion's first hole. And Tiger Woods, sporting a light-blue shirt, promptly sent his first drive to the right of the fairway and into a rough patch. He chipped his approach shot onto the green and was forced to three-putt his way to a bogey. - Matt Breen

4:47 p.m. - Woods, McIlroy will duel. But, Scott is the real star

As Thursday's most popular group tees off, here's something to keep in mind: Tiger Woods and Rory McIlroy garner most of the headlines, but in the last five majors, Adam Scott has been the real star.

As first reported on the USGA's online broadcast, Scott has been dominant since the 2012 Masters. He has only won one major in that time — this year's Masters — but he has scored a combined minus-15. He's the only player under par in the last five majors, and he's an astounding 17 strokes better than the closest player, Tiger Woods (two-over).

And Woods even has a sizeable lead over the next player, Jason Duffner, who is nine-over.

So enjoy the duel between Woods and McIlroy, but don't be surprised if Scott is the real winner. –Zach Helfand