By Andrew Both

KIAWAH ISLAND, S.C. (Reuters) -Phil Mickelson blocked out the distractions and kept his mind quiet in front of a raucous gallery to win the PGA Championship by two strokes on Sunday and become golf’s oldest major winner at the age of 50.

Mickelson battled through strong winds, shrugged off a few poor shots and kept calm amid suffocating pressure to record a one-over-par 73 at the Ocean Course, holding his nerve with Brooks Koepka and Louis Oosthuizen breathing down his neck.

In collecting the sixth major of his career, and first since the 2013 British Open, Mickelson surpassed Julius Boros as the oldest major winner. Boros was 48 when he won the 1968 PGA Championship.

“This is just an incredible feeling because I just believed that it was possible but yet everything was saying it wasn’t,” said Mickelson, who is now the only player to have claimed PGA Tour victories 30 years apart.

“And I hope that others find that inspiration. It might take a little extra work, a little bit harder effort to maintain physically or maintain the skills but, gosh, is it worth it.”

When Mickelson’s approach shot safely found the green at the final hole a wild scene ensued as fans raced to follow one of the game’s all-time greats up the fairway and completely enveloped him in a frenzied swarm.

Mickelson, who also won the tournament in 2005, later acknowledged he had been a little unnerved by the experience, while fellow competitor Brooks Koepka said he was “dinged” by spectators in the crush.

Security officials had to create a narrow path for Mickelson to navigate his way to the green, where he two-putted from 16 feet to seal the win.

‘QUIET THINGS DOWN’

Mickelson, who will get the chance to complete the career Grand Slam of all four modern majors at the U.S. Open next month, said his triumph had yet to sink in.

“It’s been an incredible day, and I’ve not let myself kind of think about the results until now, now that it’s over,” Mickelson said after finishing at six-under 282.

“I’ve tried to stay more in the present and at the shot at hand and not jump ahead and race. I’ve tried to shut my mind to a lot of stuff going around. I wasn’t watching TV. I wasn’t getting on my phone. I was just trying to quiet things down.”

Mickelson led by five shots with six holes to play, though the advantage was cut to two after bogeys at the 13th and 14th and a birdie at the 16th by Oosthuizen, who was playing in the penultimate pairing.

With victory in sight, an undeterred Mickelson showed great resolve and even flashed a thumbs-up to the crowd as he went on to reclaim a three-shot cushion with a birdie at the 16th before a bogey-par finish.

Mickelson was under no illusions that at this point in his career, when most players are long since done and dusted at the top level, wins are incredibly difficult to come by.

“It’s very possible that this is the last tournament I ever win, if I’m being realistic,” he said.

“But it’s also very possible that I may have had a little bit of a breakthrough in some of my focus and maybe I go on a

little bit of a run.”

Mickelson’s great rival Tiger Woods, who is home recovering from serious leg injuries suffered in a February car crash, was quick to congratulate him.

“Truly inspirational to see @PhilMickelson do it again at 50 years of age. Congrats!!!!!!!,” the 15-times major champion tweeted.

Oosthuizen (73) and Koepka (74) finished in a share of second place while European Ryder Cup captain Padraig Harrington (69), Ireland’s Shane Lowry (69), Englishman Paul Casey (71) and Harry Higgs (70) were a further two shots back in fourth place.