England's Matt Wallace fired a stunning 10-under-par 63 to set a daunting clubhouse target before bad weather brought play to an early end on day one of the Open de Portugal.
Waterford man Gary Hurley got into the clubhouse on two-under after a topsy-turvey round speckled with five birdies and three bogeys.
Two-time North of Ireland Amateur Champion Chris Selfridge is a shot further back thanks to an opening 72, while Ruaidhri McGee of Donegal is also one-under through three.
Wallace carded 10 birdies and no bogeys at Morgado Golf Resort to finish a shot ahead of Germany's Sebastian Heisele, who produced an eagle, nine birdies and two bogeys in his 64.
Matt Wallace is the sixth player this season to card ten birdies. The first to do so without dropping a shot. #OpenDePortugal pic.twitter.com/J5qw8nbdlH
— The European Tour (@EuropeanTour) May 11, 2017
American Julian Suri and Englishmen Paul Maddy and Jamie Rutherford were two shots further back on six under par, with former Open champion Paul Lawrie and home favourite Ricardo Gouveia on one under.
Wallace, who won six Alps Tour events last season to earn his Challenge Tour card, carded four birdies on the front nine and followed another on the 10th with five in a row from the 12th.
"It was a fantastic round really," the 27-year-old Londoner said. "It wasn't looking great at the start when the rain came in 10 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 cliche. 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."
Former Masters champion Mike Weir, who is currently ranked 1,908th in the world after failing to make a halfway cut since November 2014, was level par after three holes before play was suspended.
