(THE GUARDIAN, REUTERS) - Tiger Woods shrugged off a nasty collision with a security guard during his second round at the Masters Tournament at Augusta, Georgia in the United States.

"Accidents happen," the 14-time Major champion said. "We move on. I'm good."

For a moment it looked as though the blow might have caused him a serious injury to his ankle, but after the round on Friday (April 12), the 43-year-old insisted that he was fine.

"Apart from having four knee surgeries and three back surgeries, I'm great," he joked.

Woods shot a four-under 68, which left him on six-under 138 and one off the lead held jointly by a quintet of Major winners - Francesco Molinari, Louis Oosthuizen, Brooks Koepka, Jason Day and Adam Scott.

"It was fun," I felt like I left a few shots out there but overall it was a solid day, I hung in there and just kept grinding and tried to make a birdie here and there where I could."

The accident happened on the 14th, Woods hit his tee shot left into the crowd, who gathered close around to watch him play his second.

After he had hit it they surged in behind him and a jittery security guard came hurtling across to make sure they did not come too close. He was in such a hurry that he broke one of Augusta National's cardinal rules: no running.

Because, as the spectators' handbook puts it "for the safety of everyone, running is considered unacceptable behaviour". He slipped and his knee collided with Woods' right shin as he fell. The guard caught him side-on, and his ankle, or knee, could easily have given way.

But Woods was fine. He skipped three times, shook it off and strolled on towards the green, where he made a 28-foot putt for birdie.

It was an eventful back nine. Woods also endured a 30-minute break for bad weather after he had hit a brilliant tee shot on the 12th. He missed the putt when play resumed, but picked up two more birdies coming in.

"The last two Majors I've been right there," he said, referring to his tied-sixth placing at the British Open and runner-up spot at the PGA Championship last year.

And now he is again, gunning for his fifth Green Jacket. As for the security guard, it is not clear what happened to him, but it would not be surprising if he turns up in the far parking lot on Saturday directing the traffic.

The Woods show overshadowed everything else.

Any other time, a hobbled Day might have been the story after getting up off the deck to shoot five-under 67.

Barely able to walk after throwing out his back bending over to kiss his daughter on the practice range on Thursday, the battling Australian somehow turned in a near flawless scorecard, with six birdies and a single bogey.

"Pain is a funny thing, it goes up and down, and everybody's pain threshold is different," said Day, the 2015 PGA Championship winner.

Italian Molinari carded an error-free 67 for his best round in eight Masters that put the British Open champion in contention for a Green Jacket to go along with the Claret Jug he hoisted last year.

Koepka, who had shared a one-shot overnight lead, also deserved applause, staging a back-nine recovery after a stumbling start to the second round.

After a flawless opening round, the American had two bogeys and a double in his first six holes on Friday but the twice US Open champion was able to regain his composure, steadying himself with six straight pars from the ninth to card a 71.

It also looked like old times for Australian Scott, the 2013 Masters champion, who moved up the leaderboard with a 68.

The 2010 Open winner Oosthuizen also joined the party with a 66, while world No. 2 Dustin Johnson returned a 70 to join Woods at six-under.

There was drama up and down the leaderboard.

Patrick Reed kept his Green Jacket defence alive, making the cut with a 70 but Spain's Sergio Garcia, the 2017 champion, made an early exit for the second straight year after returning a 73.

World No. 1 Justin Rose also headed for the exit after he bogeyed the final two holes to miss the three-over cut by one shot.