Daniel Brown increased his lead to six shots after closing with a 66 to reach 11-under at the ISPS HANDA World Invitational presented by AVIV Clinics.
The Englishman was one of the afternoon starters at Galgorm and surged ahead with four birdies in his front nine followed by four more as well as three bogeys in his back nine.
"I've just been taking it one shot at a time. I know it's cliché, but obviously it's been so tricky at times, with the wind and rain today as well," said Brown. I suppose you just work out the shots as best you can and then try and execute it. Thankfully, I have done it a few times over the last couple of days.
"I think the last two events, Denmark and then the Barbasol in America, had two good finishes there and I felt like I've done enough to keep my card for next year. It feels as though the shackles are off a little bit.
"Obviously it's my first year out here, so I've been trying to put that to the back of my mind, and obviously do as well as you can each week, but I feel like I'm just going out and enjoying it a bit more now, a little bit more carefree, I suppose."
Spain's Angel Hidalgo set the early clubhouse target at five-under with a 69 at Castlerock featuring five birdies and three bogeys.
He was joined by England's Alex Fitzpatrick who closed with a 70 after producing three birdies and three bogeys.
Fellow Englishmen John Parry (69) and Eddie Pepperell (68) are tied in fourth place at 3-under alongside Spaniard Adrian Otaegui (68), Scotland's Connor Syme (69) and Norway's Rasmus Neergaard-Petersen (69).