Holland's Joost Luiten bounced back from the disappointment of an early exit in defence of his KLM Open title to claim a share of the lead after day one of the Portugal Masters.
Luiten carded seven birdies in a bogey-free 64 in Vilamoura which was matched by South Africa's George Coetzee, with England's Callum Shinkwin part of a five-strong group on six under par.
"It was a tough week last week for me, missing the cut by one, but the good thing about golf is there's always next week," five-time European Tour winner Luiten said.
"I knew my game wasn't far off and it's good that today showed I'm getting in the right shape.
"I struggled a little bit with my old driver so I got a new TaylorMade driver with a slightly bigger head and lower ball flight, more forgiving in the wind hopefully, and that really helped me. I hit it lovely today and hopefully can keep it going.
"If you hit the fairways on this course you can be aggressive into the greens -- they're quite soft -- so that was a good game plan."
In contrast to Luiten, Coetzee finished joint-third in Holland and admitted that thoughts of the European Tour's first 59 crossed his mind after carding six birdies in his first eight holes at a low-scoring venue.
"I read an article yesterday about the '59 watch' and after eight holes I was thinking if I birdie the next and the next and the next, but I guess I shot myself in the foot a little bit with that," Coetzee joked.
"You get a feeling if you can get off to a hot start you could maybe have a go at it but, in the end, I wasn't even close.
"Last week I was always slow out of the blocks -- the front nine didn't really suit my game -- but this week I started like a house on fire and thought I should do this more often."
Defending champion Padraig Harrington carded a bogey-free 67 matched by England's Jack Singh Brar, who fired five birdies and a solitary bogey in his first event as a professional.
"I'm pleased with it," Harrington told Sky Sports. "I worked my way around the golf course very well. It was not my best ball-striking round but I didn't get myself in trouble all day."
England's Scott Gregory and Scotland's Connor Syme also enjoyed successful starts to life in the paid ranks with opening rounds of 68, although Alfie Plant -- who was the leading amateur in the Open at Royal Birkdale -- struggled to a three-over-par 74.