He was tied for the lead on 14-under-par and about to play into the 18th from a greenside bunker when dangerous weather caused a delay in play.
However, Blaauw composed himself when play resumed an hour later and made a superb up-and-down to birdie the par five for the title.
“That was the best bunker shot I have played, especially when victory was on the line,” Blaauw said.
“I was very nervous, so I’m ecstatic with the chip and the putt there.” He broke through with a victory at the Origins of Golf at Simola in June and won again a fortnight later.
This week, he saw off strong challenges from Ulrich van den Berg and England’s Steve Surry, who both shared second on 14-under.
“It’s been five years and finally the hard work is paying off,” said the 27-year-old Blaauw.
“It’s a really great feeling to win again, especially before the big summer events start. Hopefully I can make it into the Nedbank Golf Challenge.”
He shot rounds of 64, 69 before the cut, and while the leaderboard was jam-packed throughout the final round, Blaauw pipped his competition at the post when he birdied the last.
The day was not won on the 18th alone, and Blaauw’s play on the stretch made him uncatchable. He made four pars to start off his second loop, before opening up the scoring.
At the 14th he drained an eight-footer for birdie and moved to 13-under before taking a soft wedge from 81 metres and hitting to two feet to match Van den Berg’s clubhouse lead of 14-under at the 16th.
“I just hung in there, because I’ve done this before,” he said.
“It puts me into another gear when the pressure is on and I knew I had to make two birdies in my last three holes, so it was nice to achieve that.”
Ross Wellington played a superb round of 65 that comprised seven birdies and no bogeys, to take sole fourth on 13-under, while Justin Harding birdied three of the last four holes to finish fifth on 11-under.