ESTORIL, Portugal (AP) Damien McGrane of Ireland and Luke Goddard of England shot 8-under 64s to share the lead after the first round of the Estoril Open on Thursday.
Stuart Manley of Wales and Eirik Tage Johansen of Norway were a stroke back.
McGrane and Goddard wondered if they had equaled the record or set a new one for the holiday resort course of Penha Longa.
Philip Price of Wales shot a 64 at Penha Longa in 1994. However, par then was 71. In recent years, the course has been lengthened to 6,903 yards and par increased to 72.
McGrane missed chances to end the record debate.
He had eight birdies in a bogey-free round, but missed close-range opportunities with his putter on the 10th, 17th and 18th greens. A 63 would have equaled his lowest score in 14 years on tour.
McGrane had a run of five birdies in six holes from the 11th.