Davis Love III still a force on PGA Tour as he fires 63 at Greenbrier

Davis Love III rolled back the years as he got off to a hot start on the opening day of the Greenbrier Classic in West Virginia.

The Old White TPC course has undergone an extensive renovation after last year's tournament had to be cancelled to devastating floods, and Love found the layout to his liking as he set the early pace with a flawless seven-under 63.

The 53-year-old, without a win on the PGA Tour since collecting his 21st title at the Wyndham Championship in August 2015, birdied four of the first five holes and came close to holing his approach shots at the first and fourth.

Love broke a run of five pars with another birdie at the 11th, and he rolled in a superb putt from over 30 feet at 14 before chipping in for another from the front of the 17th green.

The American veteran safely two-putted from long distance at the last to cap his best round of the year, and he remained the clubhouse leader until Colombian Sebastian Munoz, playing in the penultimate group, surged into a two-shot lead with a barrage of birdies in a 61.

"That's about as good as it gets," said Love afterwards. "I hit it stiff at the first hole and had a nice putt at the second and actually had a look at it at the third hole. And on four and five I was just rolling it real well and hitting it real well.

"I've been working real hard the last couple of weeks on trying to fix my swing to kind of swing around a stiff back and stiff hip. I'd given up on hitting it a long way. I've just got to hit it straight. This is the perfect golf course for me, everybody's got an opportunity from the fairway."

Munoz has missed the halfway cut five times in his 11 starts on the PGA Tour this season and has posted only one top-30 finish - a tie for 27th in Texas in April - but he went a long way to securing his card for next year with a remarkable 10-birdie opener.

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He made five birdies in six holes as he raced to the turn in just 29 blows, and he added another at the 10th before responding to his only bogey of the round at 13 with a run of four consecutive birdies which hoisted him above Love.

In-form Swede David Lingmerth birdied three of his last four holes to return a 64 and earn a share of third with Ben Martin, Canadian pair Graham DeLaet and Nick Taylor, Xander Schauffele and Danny Lee.

There was huge attention on Phil Mickelson as he made his first start since splitting with Jim Mackay, his caddie for 25 years, and employed his brother Tim on the bag for the remainder of the season.

And the siblings got their partnership off to a decent start together as the left-hander fired a three-under 67 with birdies at two of the last three holes and just one bogey on the card.