Aaron Rai set the midway clubhouse target at five under par on a testing second round at the 2020 Dubai Duty Free Irish Open.
There was a delay of 90 minutes before day two got underway due to early morning frost, with the opening group - which were meant to go out at 7.40am - beginning at 9.10am.
And to add to the later start, the elements made it even more difficult to go low during the second round at Galgorm Spa & Resort.
Overnight co-leader Rai could not improve his first round score but his even par 70 was enough to take the outright lead by one shot.
Robert Rock was also in the clubhouse at four under, while Jordan Smith and Toby Tree were still on the course.
Rai was the one of two players to card blemish free opening rounds but bogeyed the first to derail his record and drop one behind fellow co-leaders Smith and South African Dean Burmester.
He regained co-leadership by picking up a shot at the third before he dialled his tee shot into the par three seventh to four feet. And when he rolled in the birdie putt, he was the outright leader.
The 25-year-old's advantage lasted one hole though, as he could not drain his par putt from the fringe to slip back to five under.
He reached the turn at four under after failing to hole out a long par effort but picked up the shot immediately at the tenth.
Burmester dropped back to four under to leave Rai and Smith, who was among the late starters, at the top but the swirling wind made scoring difficult in Ballymena.
Rai parred the next six holes but carded his fourth bogey of the day at the 17th after three putting from 15 feet.
However, the 2018 Honma Hong Kong Open presented by Amundi champion ensured he finished the second round for level par and the lead as he rolled in a fine birdie putt from 25 feet to move back up to five under par.
Rock, who claimed the winner's cheque when Shane Lowry won this event in 2009 as an amateur despite finishing second, continued his affinity with the Irish Open by carding the joint best round of the day with a three under 67.
He birdied the second hole in consecutive days before handing the shot back at the sixth to slip to one under.
The 43-year-old, who carded a round of 60 during last year's event in Lahinch, finished with birdies at the 15th, 17th and the last to catapult him into contention in a share for second.
Smith was the last player to remain bogey free in County Antrim but he dropped his only shot at the third to sit one adrift of Rai after eight holes played. Tree also remained at four under following seven straight pars.
Playing partners John Catlin and Justin Harding are at three under alongside Australian Scott Hend in the clubhouse, while Scot Ewen Ferguson was at the same mark with three holes left to play and so was Swede Oscar Lengden through four.
