The first chance of the game came after 10 minutes when a deflected ball from the left made its way into the centre of the box where Katlego Otladisa bicycled agonisingly wide for Stars.
The same Dikwena player again gave the home side some trouble three minutes later when he escaped down the right and crossed dangerously, before the ball was scrambled away.
United had to wait 24 minutes for their first chance and it came via a thumping half-volley from Evans Rusike that stung the palms of Dino Visser in goal.
That effort seemed to spark the hosts into action and Devon Saal then had a deflected effort from the edge of the box strike the side-netting after half-an-hour.
Then came the miss of the game as Mohau Mokate started the move with a brilliant through ball to Rusike, who back-heeled to Devon Saal and he in turn found the Zimbabwean in the box, with the final shot pushed wide with only Visser to beat.
Straight after the restart, Lebohang Maboe came close to breaking the deadlock with a strike from the edge of the box that forced Visser to turn wide.
Stars finally had a second-half opening after 65 minutes as substitute Robert Ng’ambi pirouetted beautifully on the left side of the box and fired a low shot into the side-netting.
The Malawian had another chance five minutes later that was volleyed over, before Rusike squandered another opening when Bandile Shandu floated in perfectly from the right, with the striker this time miskicking the ball wide.
With time running out, Mxolisi Kunene had a goal ruled out for off-side against Mokate as the match headed into extra time.
There were two chances of note during the additional 30 minutes – one wasted by Maboe at the death when he shot wide, with the earlier one headed off-target by Rusike, who by then was shot of his confidence. Visser was then the hero as Stars progressed.