Pratt, Matthew Baldwin, Johan Edfors, Jean-Baptiste Gonnet and Kim Gi-whan all shot 5-under-par 67 and share the lead after Thursday's play.
However, the bulk of the 156-player field is yet to finish first-round play. Rain and fog caused a delay of about 2 hours and play was suspended because of darkness. The first round is to continue at 7:30 a.m. Friday.
Among those still on the course are Louis Oosthuizen and Tommy Fleetwood, who are both 4-under. Oosthuizen has played 16 holes and Fleetwood 17. They are tied with Peter Lawrie and Lee Jung-hwan, one stroke off the lead.
Nine more players are at 3-under.
Pratt's flurry of birdies on Nos. 16-18 combined with birdies at 8 and 11 for his bogey-free 67. Gonnet was also bogey-free, while Edfors, who was 5-under on the front nine, had one bogey Thursday, and Baldwin had two.
Kim had birdies at Nos. 5-6 but posted a bogey at the ninth hole. He had three consecutive birdies at 13-15 and a bogey at 16 before closing with an eagle at the par-5 18th.