Blustery conditions made scoring difficult, but the British Masters champion stood one under after 12 holes only to falter with a double bogey six at the 13th.
The 21-year-old's response was emphatic and underlined his growing standing on the tour in only his first season.
He birdied the next hole and, after a par at the 15th, carded birdies at holes 16, 17 and 18 for a seven-under-par aggregate (68 69) to stand equal ninth.
His fellow Sheffielder Danny Willett was tied fifth after round one with his seven-under-par 65, but dropped back to 19th place.
He required nine shots more to negotiate the course than he had on Thursday and after his 74 stands at five-under-par 139.
Willett is now just one shot ahead of former world No 1 and Race to Dubai leader Rory McIlroy, whom he trails by 400,000 points as he attempts to be crowned Europe's No 1 player for the season.
Scotland's Russell Knox hopes to turn his late entry into the final World Golf Championship event of the season into a first European Tour title and a £900,000 pay day after a superb second round in Shanghai.
Knox was initially seventh reserve for the £5.5m event, but discovered last week he had secured a place in the 78-man field when JB Holmes withdrew.
The 30-year-old from Inverness made the most of his good fortune by carding a flawless 65 to lie two shots behind American Kevin Kisner, who added a 66 to his opening 64 and has not dropped a shot in 36 holes.
Knox found out he would be making his WGC debut while playing in the CIMB Classic in Malaysia last Friday and praised his wife Andrea for making the necessary arrangements - and also stepping in as a temporary caddie.
"My wife was a superstar and she filled out all the forms for us," said Knox, who made his Open debut at St Andrews in July after Rory McIlroy was forced to withdraw due to the ankle injury he suffered playing football with friends.
"While we were playing on Friday she took all the stuff to the Chinese embassy in Kuala Lumpur and had it processed. Then we had to wait around till Monday at 2pm to get them back and they gave us our passports.
"We flew here on Tuesday morning but my caddie didn't have proof of accommodation so he was a day behind us. So when we got here my wife caddied for me. We got a stand bag from the pro here and chucked the clubs in and played the quickest practise round ever - and she complained heavily for the last nine holes."
Kisner is the only player in the field not to have dropped a shot this week, despite not playing a practice round after suffering a back injury in the final round in Kuala Lumpur.
"It's beyond my expectations," Kisner, who lost three play-offs on the PGA Tour in 2015, said of his form. "I'm making a lot of putts and that's fun keeping the round going when I miss a green. I'm looking forward to the weekend.
"Having an injury probably lowers your expectations and you play better. So probably something to learn from that."
Frustrated McIlroy, who recovered from a bout of food poisoning to card a 68 on Thursday, went within inches of a hole-in-one on the 12th, but bogeyed the 13th after missing the green and was furious with another pulled iron shot on the short 16th, slamming his club into the bag and then barely bothering to line up a par putt from four feet, which he duly missed.
Things looked set to get even worse on the 18th when the world No 3 found water with his approach and had to let two more balls roll into the hazard as he took a penalty drop on a steep slope short of the green.
However, the 26-year-old pitched to four feet to save par and signed for a level-par 72 which left him four under par alongside Masters and US Open champion Jordan Spieth, who needs a top-13 finish to replace the absent Jason Day as world No 1.
"I didn't play very well. I was just a bit flat out there," McIlroy said. "I've left myself a lot to do over the weekend but hopefully I can shoot a couple of good scores and get myself back up the leaderboard.
"I wouldn't say I'm 100 per cent. I struggled to hit balls on the range, got a few cramps in the stomach. But I took a couple of tablets and it sort of went away as I went through the round."
Overnight leader Branden Grace, who could overtake McIlroy at the top of the Race to Dubai with a win on Sunday, added a 71 to his opening 63 to lie third on 10 under par, with Patrick Reed and China's Li Haotong a shot further back.