Munyai again displayed his immense potential, taking second place in the Men's 200m event in 20.10 at the Athletics Gauteng North League Meeting hosted by Tuks.
The exciting 19-year-old Rio Olympian bettered the SA Under-20 mark of 20.16 which had been set by Riaan Dempers in Germiston in April 1995.
He also narrowly missed out on breaking the national junior 100m record of 10.19, grabbing second spot in the shorter event in 10.20.
Simbine was equally impressive, starting his season with a bang.
The 23-year-old Rio Olympic finalist clocked 9.93 to secure victory in the 100m dash and went on to win the 200m in a Personal Best of 19.95, but his half-lap time was 0.08 outside Anaso Jobodwana's SA mark, clipping 0.21 off his own career best.
Simbine’s performance in the shorter sprint was 0.04 outside his own national senior record, but setting the fastest time ever run in South Africa.
He joined 400m world record holder Wayde van Niekerk as the only two South Africans to have run under 10 seconds over 100m and sub-20 seconds over 200m.
Elsewhere on Saturday, Frans broke the SA 30km record at the NMBM Human Race in Uitenhage, Eastern Cape.
The unheralded 27-year-old athlete shattered his Personal Best by more than five minutes, defending his title at the annual race in 1:30:54.
He edged out marathon specialist Lusapho April, who crossed the line nine seconds later in second position.
