Victor Perez birdied four of the last five holes to hold a four-way share of the lead on six under par at the Genesis Scottish Open.
Sepp Straka, Nicolas Echavarria and Jake Knapp matched the world number 10 in shooting 64 at the Renaissance Club.
Scotland’s Calum Hill, England’s Marco Penge and Marcel Siem and Matti Schmid remain in contention just a shot behind the leading quartet.
Perez is not getting ahead of himself after a strong finish put him into a good position.
“I’ve always kind of enjoyed keeping the ball down and long putts from off the green,” the Frenchman said.
“I think it may play in my hand a little bit better with what I’m good at. So, yeah, enjoyed a very good first day, but a lot of golf left.”
Rory McIlroy is four shots adrift after he finished his round with three straight birdies on the way to carding a two-under-par 68.
McIlroy said: “I definitely finished the round better than I started it. Felt like it was a bit of a slow start.
“I think when you come back over here, links greens, they’re a lot slower than what we’re used to. So 3-putt on 1, and then did well, but then 3-putt 2nd as well. So that got me off and running. Then I felt like I played some good golf after that.
“Obviously finished great. I was saying to the guys over there, I struggled a bit in left-to-right wind. Right-to-left winds I was okay with, but seemed like the holes I got myself in trouble was when the wind was to the left.
“Something to try to work on over the next three days.”
Defending champion Robert MacIntyre also shot a two-under 68, while world number one Scottie Scheffler carded a three-under 67.
Scheffler said: “I feel like I could have got a little bit more out of my round. I felt like I did some good things that I didn’t quite get rewarded for after my start but, you know, three under, I wish I could have had a couple of those bogeys back but, overall, not too bad.
“This golf course in particular, the wind has a big effect on the way the golf course plays. I think tomorrow in the afternoon we’ll get the total opposite wind than we had today.
“So that will be a new challenge and something I’ll get mentally prepared for.”
