Defending champion Pádraig Harrington carded his first bogey-free round for more than two months when he opened with a 67 to lie just three off the lead in the Portugal Masters.

The Dubliner (46) has been unable to find much rhythm this season having been forced to miss three months of the campaign following neck surgery in March and another two weeks in June after getting hit on the elbow by an amateur in a freak accident.

But he showed no signs of rust at the Dom Pedro Victoria Golf Course at Vilamoura, making four birdies in a six-hole stretch in the middle of his round.

That was good enough to leave him tied for 16th on four-under-par behind Dutchman Joost Luiten and South Africa's George Coetzee, who shot seven under par 64s to lead by a stroke from China's Ashun Wu, Australia's Jason Scrivener, Frenchman Grégory Havret, Italy's Nino Bertasio and England's Callum  Shinkwin.

"It brings more stress," Harrington told Sky Sports when reflecting on his bid to win the title for the second year in a row.

"It's not as easy to play a tournament as defending champion. Not that many people tend to win the return."

The three-time Major champion started on the back nine and picked up shots at the 14th, 15th and 17th to turn in 33 before following another birdie at the first with eight straight pars.

Shane Lowry birdied the last to sign for a two-under 69, the Offaly man level par at the turn but getting in the red as he picked up two shots in his last five holes to end the day tied for 41st in his first start after a four-week break.

It was a tough day for former Irish Close champion Chris Selfridge who made his lone birdie of the round at his final hole for a three-over-par 74.

The leaders have been struggling for form of late, but with Luiten (31) having a new driver in the bag and Coetzee having recently spent some time back in his native South Africa, they found their stride in some style.

"I'm very happy, seven under - no bogeys, seven birdies - that's what you want every day," said Luiten, who has missed three of his last four cuts.

"I knew my game wasn't far off and the good thing about golf is there's always next week and this week it feels nice and hopefully we can keep it going."

Coetzee had missed four cuts in a row before finishing in a tie for third in the KLM Open last week and after starting at the 10th, he looked to be carrying that momentum in style as he birdied six of his first eight holes to turn in 30.

Admitting he was thinking of a 59, he bogeyed the second but picked up further birdies at the fifth and eighth to card his 64.

"I read an article yesterday about 59-watch and after eight holes I was thinking, 'okay, if I birdie the next one and the next one and the next one....'," he said. "I guess I shot myself in the foot a little bit today but I was quite happy with the way things went."