Renato Paratore turned in 31 to set the early pace as day one of the Portugal Masters got under way at Dom Pedro Victoria Golf Course.
The Italian made five birdies from the tenth to get to five under and lead the way by one shot from England's Richard Bland and China's Li Haotong.
Major Champion Sergio Garcia was then in a group of seven players two shots off the lead.
Paratore has made just eight of 21 cuts this season but finished in a tie for second at the Porsche European Open and is on course for a third consecutive top 100 finish in the Race to Dubai Rankings presented by Rolex.
Bland is a three-time Challenge Tour and two-time Qualifying School graduate who is still searching for that elusive first European Tour win as he edges towards his 450th event.
The 45 year old enjoyed a career-best year in 2016 as he finished 28th in the Rankings but needs a big finish to the season to keep his card this term as he currently sits 175th.
Li has no such worries after launching himself to international attention earlier this season as he held off the challenge of Rory McIlroy to win his second European Tour title at the Omega Dubai Desert Classic.
Bland got off to a blistering start, sandwiching an eagle on the par five 12th with birdies on the tenth, 11th, 14th and 15th before bogeying the 17th and 18th.
That opened the door for Paratore who made gains on the tenth, 12th, 14th, 15th and 18th.
Li started birdie-birdie-birdie but dropped a shot on the 14th before eagling the par four 15th in his first six holes.
Spaniard Garcia birdied the tenth, 12th and 14th in his first five holes to sit alongside countryman Alejandro Cañizares, English trio Laurie Canter, Ross Fisher and Jordan Smith, South Korean Soomin Lee and South African Zander Lombard.
