The Eagle Canyon golfer opened with a two-under-par 72 to edge clear of Opperman from Gauteng North and De Beer from Eastern Province.
Leach reversed a bogey-bogey start with a brace of birdies at three and four and countered another drop at five with birdie at the par four sixth.
He collected a third gain at the short eighth and briefly dipped to two under with a birdie at 10, but lost the advantage with his four bogey at 11. The BDGA Golf Academy player settled with a run of pars from 12 and took pole position when he finished birdie-par.
De Beer from Port Elizabeth offset a trio of bogeys with four birdies to finish at one under, while local favourite Opperman managed to cancel two bogeys and a costly double at the par four seventh with four birdies before he closed with a birdie at the par-five 18th to grab a share of second.
Ge-Rico Muller from Free State, Alex van Wyk from Southern Cape and Central Gauteng’s Keanu Pestana finished in a tie for fourth on even par, with Dehan Joubert from Eastern Province a further shot adrift.
FIRST ROUND SCORES – Top 10
70 Bryce Leach
71 Dawid Opperman; Kyle de Beer
72 Ge-Rico Muller; Alex van Wyk; Keanu Pestana
73 Dehan Joubert
74 Jayden Schaper; Sentanio Minnie; Marcus Taylor
PHOTO – Dawid Opperman from Pretoria Country Club.