The opening event of the 2022 DP World Tour season had already been reduced to 54 holes to allow non-South African resident players, caddies and tournament support staff return to their home countries, with international travel restrictions imposed on the country after the emergence of a new COVID-19 variant.
Home favourite Lawrence had matched his lowest DP World Tour round on days one and two, with a pair of 65s sending him into the weekend at Randpark Golf Club at 12 under and with a four shot lead.
Weather delays over the first two days meant that the second round had to be completed on Saturday morning but when the rest of the field completed their own second rounds, Lawrence was still four ahead.
A bogey on the first trimmed his advantage but more dangerous weather swept in at 12.12pm and, with no prospect of getting play completed on day three, the result was declared based on 36-hole scores.
The win also hands Lawrence, Lombard and Chesters a place in the field for The 150th Open Championship next summer, with Norris already exempt.
Lawrence takes his first win in just his 22nd DP World Tour event, with six made cuts and a best finish of 17th in the previous 21.
He now adds to his Sunshine Tour victory at the 2019 Vodacom Origins Stellenbosch and has a DP World Tour exemption until 2023.
"It's so surreal," he said. "I don't think anyone thought it would turn out this way, to finish on a Saturday afternoon but I'm just really thankful. It's a life-changing moment for me.
"It's a lifelong dream that has come true. Unbelievable golf these last few days.
"I had my card on the Sunshine Tour but I really wanted to move on to the next step. It happened so quickly. There's a lot of things that could happen next year. You know you're on the Tour and you don't have to worry about invites and it gives you a lot of confidence.
"You don't get these opportunities often. I've had four years of co-sanctioned events so you build up experience but it's just unbelievable.
"It's been a goal, you want to see yourself up there but the last year and a half of Covid it's been tough so you sort of see your dreams fade. For it to change this week is unbelievable."
Spaniard Angel Hidalgo and Frenchman Frederic Lacroix - who picked up two shots as he finished his second round on Saturday morning - were at six under, a shot clear of South African Hennie du Plessis.