Matt Wallace remained in front as the first round of the weather-affected Open de Portugal at Morgado Golf Resort was completed on Friday morning.
The Englishman reeled off ten birdies - including five in a row from the 12th - in his sparkling 63 on Thursday before play was suspended due to thunder and lightning, with the afternoon starters still out on course.
The first round resumed at 8.30am on Friday but no-one could catch Wallace, who remained one shot clear of nearest challenger Sebastian Heisele.
Heisele carded an eagle, nine birdies and two bogeys in his opening 64 on Thursday to get to nine under par.
Englishman Ashley Chesters was another two shots back in third after completing his first-round 66 on Friday morning.
Wallace, who won six Alps Tour events last season to earn his Challenge Tour card, made a strong start on Thursday morning, notching four birdies on the front nine to reach the turn in 32.
The 27 year old began his back nine in style, making another gain at the long tenth before firing birdies at the 12th, 13th, 14th, 15th and 16th to propel himself to the top of the leaderboard.
I just took one shot at a time and we had a really good day out there - Matt Wallace
Wallace then safely parred his final two holes to head into the clubhouse on ten under.
After his flawless first round, Wallace said: "It was a fantastic round really.
"It wasn’t looking great at the start when the rain came in ten minutes before my tee time. Then it stopped just as we got on to the tee, so that was kind of a good omen.
"It was the old cliché. I just took one shot at a time and we had a really good day out there.
"Everything was working well to be honest. Everything clicked. I made two good par saves on the front nine to keep the momentum going.
"After that every hole was at least a birdie chance, so it was a really good day.
"It’s been a continuation of a good start to the season. I’ve enjoyed it, I love coming out here and playing and hopefully we can keep this going for the next three days."
Fellow early starter Heisele made three straight birdies from the third before dropping his first shot of the day at the sixth.
But he bounced back with an eagle at the seventh and a birdie at the ninth to cover his front nine in 31 strokes.
The German started his back nine with a birdie at the tenth but carded a bogey at the par-three 11th to fall back to five under.
He then produced four birdies in his next five holes to finish his first round a single shot behind Wallace.
"Nine under is a great start, I’m happy with that," said Heisele. "I put together a few birdies in a row on the front and the back, which helped.
"It was good to see Matt Wallace going out in front of me and giving me something to chase down. It’s just a bit of friendly rivalry. Seeing him chase up the board there a few groups in front of me was great, it was fun trying to keep up.
"It was a steady round, I had a couple of good putts, but then there were a couple of short putts that didn’t go my way so it could have been better, but I’m happy with that."
The second round got under way at 11.30am on Friday.