Paul Casey was four shots further back after a 72, with world number three Rory McIlroy on course to make the halfway cut after adding a 71 to his opening 74 and Graeme McDowell one under par after also shooting 71.

Fitzpatrick was the leading amateur in the 2013 Open at Muirfield and won the US Amateur title a month later, before making a successful transition to the paid ranks in 2014.

Victory in November's DP World Tour Championship came two years to the day since he gained his card via the qualifying school and saw Fitzpatrick eclipse Nick Faldo's record as the youngest Englishman to win three times on the European Tour.

It also gave him the security of a five-year exemption on the European Tour and a PGA Tour card is the next goal for the world number 30, who carded five birdies and two bogeys in his 69.

Fitzpatrick, who was seventh in the Masters last year and made his Ryder Cup debut at Hazeltine, followed a birdie on the second with his first bogey of the week on the fourth, before adding four birdies and a bogey on the back nine.

Making just his third start of 2017 due to a rib injury, McIlroy bogeyed his first two holes after a wild tee shot on the 10th and another errant drive on the next, but bounced back with a birdie on the 12th and an eagle on the 16th.

The four-time major winner had been unhappy with his approach to the par five after a 326-yard drive, but holed from 30 feet to get under par for the day.

However, the 27-year-old promptly found water with his tee shot on the 17th to give both shots back, before completing an eventful nine holes with a birdie on the 18th.

The front nine was a more sedate affair as McIlroy recorded a solitary birdie and eight pars to finish two shots inside the projected cut.

Fitzpatrick told Sky Sports 4: "Everything's coming together slowly. I'm going to do a little bit of work this afternoon, just got to keep on top of things going into the weekend and hopefully push on.

"The Masters is three weeks away now and hopefully I can keep this form going into it. Everyone tries to peak around there, it's difficult but someone's got to do it, and it's just a case of keep working at it and keep it consistent."

Fitzpatrick's overnight co-leader Emiliano Grillo quickly emerged as the biggest threat to Hoffman's lead, the Argentinian holing a bunker shot for an eagle on the 12th and chipping in for another on the 16th.

That took Grillo to nine under par and a shot off the lead, with Italy's Francesco Molinari four under for his round and six under overall with four holes remaining.