Xulu had scored a quite remarkable own-goal with seven minutes remaining in regulation time to make it three goals each to send the teams to extra-time in the Cup quarterfinal contest, but with the sides seemingly headed to penalties he scored the goal that sealed the result.
That strike came in the 115th minute when AmaKhosi captain Siphiwe Tshabalala sent the ball into the area from a setpiece, and Xulu produced a spectacular bicycle-kick finish to secure the win for his side.
Chiefs did manage a fifth with time up, as Hendrick Ekstein was on target to make the scoreline more flattering for the defending champions.
Earlier, Kurt Lentjies stunned the Chiefs defence as he scored the opener for the visitors in the eighth minute. The fiery midfielder snapped up a loose ball near the centre circle, and with just the goal ahead he surged into the box, rounded Chiefs keeper Reyaad Pieterse and fired into the open target to make it 1-0 to Maritzburg.
Tshabalala had a sharp chance just before the quarter hour mark, but his first-time shot from a Tsepo Masilela cross was directed into the side-netting.
