The 22-year-old speedster charged to victory in 9.96 seconds, chopping 0.01 off the previous national mark he had shared with training partner Henricho Bruintjies.
“It’s an amazing feeling,” said Simbine, who narrowly missed out on a place in the final at last year’s World Championships.
“It’s my first race of the season so I’m surprised with my shape, but I’m excited about where I am now.
“I just hope I can build on this.”
Simbine felt he could have gone even quicker at the high-altitude Pilditch Stadium, after a relatively sluggish start.
“The first phase was not as good as it could have been, but from the 40m mark everything came together,” he said.
Simbine confirmed he would turn out next in the Gauteng North provincial championships this weekend.
“I haven’t decided yet, but I might focus on the 200m just to get one in my legs.”