(Photo credit: Michael Madrid-Imagn Images)

Zach Johnson birdied the par-5 18th hole to grab a one-point lead at the Mitsubishi Electric Classic after Friday's first round at TPC Sugarloaf in Duluth, Ga.

For the first time, the Mitsubishi Electric Classic is using the Modified Stableford scoring system to encourage aggressive play. Rather than scoring relative to par, points are awarded per hole -- minus-1 for a bogey, zero for par and two for birdie. Eagles are worth five points while double bogeys are minus-3.

It is the first time since 2002 that the PGA Tour Champions is using Modified Stableford, according to the tour.

Johnson did not seem to mind the switch, calling himself 'a conservatively aggressive guy.' The two-time major champion turned 50 in February and won his first title on the senior tour in March.

'There's opportunities on certain courses, and this would be one of them, where I'm going to push a little bit more, I'm going to hit the driver instead of what have you,' Johnson said. 'So I think the beauty of this place is the character. You've got short, you've got long, you've got left, you've got right, you've got up, you've got down. You can be aggressive on certain holes, you can hit driver a lot of places, you can lay it back in a lot of places. So you've got to be committed, and it gives you options.'

He rolled in six birdies with one bogey over his first eight holes. The scoring slowed down on the back nine, but he jumped from +13 to +15 by two-putting the finishing par-5.

That put him one point ahead of Ben Crane and Thailand's Thongchai Jaidee. Tied for fourth at +12 were Paul Stankowski, Retief Goosen of South Africa and K.J. Choi of South Korea. Last year's champion under traditional stroke play, Jerry Kelly, is tied for seventh at +11.

Jaidee managed to card seven birdies without a bogey.

'You have to make more points because ... par (is) nothing,' Jaidee said. 'That's why we gameplan to attack the hole. When you hit in the fairway, you have a short iron, you try to attack the pin. That's why we do it today. And good thing to me, I had pretty good iron today. Putting working today.'

Crane turned 50 this year like Johnson and finished second at last week's Senior PGA Championship, his first senior major.

He had to overcome two bogeys on his round Friday but it helped to birdie three of the final four holes.

'Just didn't play as great as I scored, but that's the way it works in this format,' Crane explained. 'Actually, Retief and I both shot 66 and I had 14 points and he had 12. Had some bogeys in there that don't cost you as much. All in all, just thankful. I really putted well coming down the stretch there, gave myself some opportunities, so just a fun day.'

--Field Level Media