Scotland's Marc Warren has carded an eight under par 63 to become the early leader of the Portugal Masters in Vilamoura.
The 35-year-old began with six successive birdies at Victoria Clube de Golfe before adding a further three after blemishing his card slightly with a bogey on the seventh.
Fellow Briton Eddie Pepperell also made a strong start to the competition on Thursday as he seeks to secure his Tour card for next season.
The 25-year-old, who needs to retain his current ranking to make the cut, sits one shot off the overnight lead in joint-second position with Finn Mikko Korhonen, America's David Lipsky and the British pair of Matthew Baldwin and Callum Shinkwin.
Baldwin, 30, needs a top-two finish this week to keep his card and he hit eight birdies in the opening round, although a bogey on the seventh blotted his copybook.
Chris Paisley is among a group of five players a shot further back on six under, along with Swede Jens Fahrbring, who also needs a top-two finish, and Spaniards Alejandro Canizares and Nacho Elvira.
Three-time major winner Padraig Harrington, who chipped in for an eagle on the par-four 15th, will resume on five under on Friday, with British players Ben Evans, Ryan Evans, Paul Lawrie and Oliver Fisher also tied on the same score.
Defending champion Andy Sullivan, who last year secured victory by a tournament-record nine shots, is four strokes off the pace on four under.
