Despite the home side suffering a red card as early as the 38th minute, it wasn't until extra time when Chiefs finally managed to break the deadlock and wear down their brave opponents, as goals from Christian Saile Basomboli and Ashley du Preez saw them safely through to the next round of the Cup competition.
Chiefs coach Arthur Zwane handed new arrival Basomboli his first start - a move that would eventually pay rich dividends - while also recalling defender Zitha Kwinika.
The first real chance fell to Maritzburg when Kwame Peprah had time and space to shoot from close range, though goalkeeper Brandon Peterson was able to parry the ball away for a corner.
Just past the half-hour mark, the Team of Choice were nearly in again when Kwame Peprah's curling effort from outside the area looked destined for the goal, only for Peterson to come good again with a superb one-handed save.
But disaster struck for the home side not long before half-time when Travis Graham was shown a second yellow card for a reckless challenge on Siphiwe Tshabalala to reduce them to 10 men.
Maritzburg coach Fadlu Davdis immediately made a couple of changes to adopt a more defensive structure, with Tebogo Tlolane and Keegan Ritchie making way for Lungelo Bhengu and Jose Ali Meza.
Chiefs did finally come to life just before the break when a well-placed strike from Ashley Du Preez from outside the area forced King Ndlovu into a smart save.
Hopes that the Team of Choice would crumble in the second half with so much time left to play failed to materialise as they doggedly defended their goal with 10 men, despite Chiefs creating several decent chances.
Had it been a match lasting only 90 minutes, Maritzburg would have emerged with a battling point, but as it was a knock-out competition, they had to try and survive for another 30 minutes of extra time football, a feat that proved too much for the tiring players.
It took just two minutes of extra time for Basomboli to finally put Chiefs ahead, swooping in and bundling the ball in from close range after Ndlovu made a hash of Zitha Macheke's cross.
Amadou Soukouna nearly drew the home side level in the second period of extra time after hitting his shot against the post, but instead it was Chiefs who put the result beyond question when Du Preez latched onto a cross from Happy Mashiane at the back post and made it 2-0 to Amakhosi.