The world number one brushed aside two torrential rain showers in Northern Ireland to fire a seven under par 64, the best round of the week so far, and send an ominous warning to his title rivals.
He is 10 under overall at the halfway stage, one stroke clear of Matthew Fitzpatrick.
Fitzpatrick produced a brilliant 66 to boost his hopes of becoming the first English winner since Nick Faldo claimed his third title in 1992.
Brian Harman, the 2023 champion, is one shot further behind on eight under, alongside China’s Li Haotong.
Home favourite Rory McIlroy carded a two under par 69 to reach three under for the tournament, but is already seven strokes off the pace.
Scheffler struggled off the tee on Thursday but still scored a first-round 68 to sit one stroke off the overnight lead.
He got his second round off to a flying start with a first-hole birdie in driving rain.
The PGA Championship winner then reeled off three consecutive birdies from the fifth hole, including a 34-foot putt down the hill on the par-three sixth.
A second downpour played its part in a rare bogey on the 11th, but Scheffler quickly responded with his sixth birdie of the round on the par-three 13th.
The three-time major champion picked up another shot on the treacherous 16th, dubbed “Calamity Corner,” before reaching 10 under on the 17th despite hitting his drive into the crowd.
One last birdie putt pulled up just short of the last hole, but Scheffler will be a firm favourite going into the weekend as he eyes his fourth win of the year. (AFP)