Alviro Quiros' knowledge of his home course was of little advantage as six others tied the 2008 champion for the lead after the first round of the Portugal Masters on Thursday.
All seven shot 6-under 65s, four of them finishing their rounds with birdies on their last holes at Oceanico Victoria Golf Course.
Nine other players shot 66. In all, 68 players, more than half of the field, went under par in ideal conditions.
Jamie Donaldson of Wales had the lead at 7 under until he bogeyed the 8th, his 17th hole.