Trailing by three shots overnight, defending champion Brendan Lawlor, 27, impressed in damp second-round conditions at Woburn, posting a second successive 71 for a two-under-par total of 142.
Lawlor, who has Ellis–van Creveld syndrome, leads by a stroke after England’s Popert, 25, battled to a three-over 75 for a total of 143, aided by a closing birdie.
Lawlor stated, “I’m feeling confident with my game and excited for the challenge tomorrow.”
Last year’s inaugural Championship saw Lawlor edge out Popert, who has cerebral palsy, by two shots, setting the stage for another thrilling showdown.
Popert, the world number one, aims for a tenth G4D Tour triumph, while Lawlor seeks to defend his title for the first time.
Canadian Chris Willis sits in third spot on four-over-par, with 18-year-old Englishman Thomas Blizzard a shot further back.
Lachlan Wood from Australia and home player Mike Browne are on six-over. Daphne van Houten leads the women’s players in a share of 24th place.
Established last year, the Championship, held in partnership between the DP World Tour and The R&A and supported by EDGA (formerly the European Disabled Golf Association), is one of the most inclusive events ever staged.
The G4D Open features nine sport classes across multiple impairment groups, with 80 men and women players from 19 countries.
Contested over three days and 54 holes of gross stroke play, it crowns both men’s and women’s champions and offers gross prizes in various sport classes.
Earlier today, a revolutionary prosthetic arm, the first of its kind globally, was trialled by primary-aged children at a special coaching session at Woburn.
This innovation aims to enhance the ability of players with upper limb differences to effectively use a golf club.
Spectators are welcome at Woburn for The G4D Open, with free attendance and car parking.