Chiefs have themselves to blame after dominating for much of the 90 minutes, but failing to take their chances.
The visitors were on the back foot from the first whistle, but held firm throughout the match to record a win over their much fancied opponents.
First with an attempt at goal for Chiefs was Siphiwe Tshabalala who in the fifth minute received a cross from George Lebese, but from distance Shabba couldn’t keep his shot down and it sailed over the bar.
Then it was Lebese’s turn to try his luck in the eighth minute, but his shot was blocked by Mbulelo Mabizela for a corner. From the resultant set piece, Tefu Mashamaite had a free header from Tshabalala’s ball but the defender fluffed the opportunity with his header going wide.
Shabba was heavily involved early on and it was his flicked ball that found Lebese with some space in the 14th minute but the latter’s long-range shot was saved by Jackson Mabokgwane.
In the 20th minute, Tshabalala was fouled not far from the box and Bernard Parker stepped up to take the free kick but saw his attempt saved by Mabokgwane, who needed a second attempt to keep Chiefs at bay.
Probably the best chance of the first half fell to Black Aces striker Tendai Ndoro in the 30th minute. Former Chiefs midfielder Abia Nale put in a cross from the right and Ndoro was very close to the opener but his curling shot was wide off target.
There was controversy on the stroke of halftime when Ndoro appeared to be heckled down by Willard Katsande in the box but there was a real let off for Chiefs as the referee Khulasande Qongqo waved play on.
The score at the break was 0-0.
For the start of the second half, Lebese was taken off in favour of Matthew Rusike as Chiefs head coach Stuart Baxter looked to seal the tie in the next 45 minutes.
The chances were far and few between early in the second half, but a real opportunity did come in the 62nd minute when Siboniso Gaxa played through an inch-perfect cross but Parker’s attempt was straight into Mabokgwane’s hands.
Parker could have had the easiest of tap-ins in the 73rd minute but faced with an empty net after a cross by Katlego Mphela, Parker missed the glorious chance from close range as he blasted over much to the dismay of Chiefs fans.
Masilela was fouled in the 83rd minute, which presented Chiefs with an opportunity to break the deadlock but from Shabba’s free-kick Katsande’s header was just wide.
After all the missed chances, Chiefs were made to pay right at the death. In injury time, Aces' Timm, who had earlier come off the bench, ran onto Nale's perfectly weighted through-ball to poke him, handing the Mpumalanga side a 1-0 win.