(Photo credit: Andrew Dolph / USA TODAY NETWORK via Imagn Images)

PGA Tour Champions rookie Zach Johnson carded an 8-under-par 64 on Friday to take the first-round lead at the Portugal Invitational in Algarve.

Johnson posted nine birdies and one bogey at The Els Club Vilamoura to build a one-shot lead against Slovakia's Rory Sabbatini, who is in solo second place after a bogey-free round with seven birdies.

Alex Cejka of Germany, Charlie Wi of South Korea, Padraig Harrington of Ireland and Mikael Lundberg of Sweden are tied for third place at 6-under-par, with six golfers another shot behind in a tie for seventh place.

Johnson, 50, already has won three times on the senior tour this season, including two of his last three tournaments at the Principal Charity Classic and Kaulig Companies Championship. He finished T7 at last week's Senior Open.

'I would argue it's the best tour in the world,' he said. 'I'm enjoying it. I would love to have my family out more, but I know my wife's enjoying it as well. She likes to watch golf and take a nap, so that works out well.'

Johnson opened with birdies at the first three holes, suffered his only bogey at the par-4 13th hole and grabbed the clubhouse lead with another birdie at the par-4 18th. He birdied all five par-5s on the course.

'It was just solid,' Johnson said. 'There were very few stressful situations. I hit an errant tee shot on 13, just complete brain meltdown, just lack of focus on the tee shot, and it cost me a bogey. But other than that, it was a very simple day.'

Sabbatini started on the back nine and also played the par-5 holes in 5-under.

'The par-5s are scoring opportunities but you still have to be very cautious because if you try and be overly aggressive on them, they tend to bite you pretty hard,' Sabbatini said. 'So you've got to try and remain within yourself on those holes and give yourself opportunities, but be prepared that if you try and take off a little bit more than you should, it's probably going to result in either a par if you're lucky and sometimes some bogeys.'

This is the first PGA Tour Champions tournament ever held on Portuguese soil.

Sixty-four of the 78 golfers shot even par or better on Friday. In addition to Harrington, the field includes World Golf Hall of Famers Retief Goosen, Bernhard Langer and Colin Montgomerie.

--Field Level Media