Overnight leader Liam Johnston could only add a 74 to his opening 61 to slip back to seven under par and a nine-way tie for third place at the halfway stage of the Portugal Masters.
The Dumfries man admitted: “I saw the bite of the course today. I just struggled with my swing a little bit, but it’s fine. I grafted really well. I’m actually really proud with only shooting three over today.
“The rough was tough and I kept hitting it in and leaving myself in bad spots. I actually made a lot of good putts for par so I’m glad to still be in the hunt after a day that didn’t feel good.”
World No 670 Julien Guerrier established a commanding lead. Guerrier, who won twice on the Challenge Tour in 2017 but is seeking a first European Tour title, added a second round of 66 to his opening 62 in Vilamoura.
At 14 under par, the 35-year-old Frenchman ended the day five shots clear of American Sihwan Kim, whose erratic 66 included a back nine featuring six birdies and three bogeys.
“I’m feeling great,” said Guerrier, who played just five events in 2019 due to injury. “It looks easy but it’s not. After you shoot nine under it’s always tough to make a good score, so I’m really happy to play well.”
Pre-tournament favourite Tommy Fleetwwood is 11 shots off the pace after recovering from playing the first seven holes in three over par to return a 71.