Sundowns needed Chiefs to lose to Polokwane City in a simultaneous fixture and defeat Dikwena to have any hope of extending the title race.
However, Amakhosi thumped Rise and Shine 4-1 to claim championship honours with three games to spare.
Downs could not see off Stars as Alje Schut's opener was cancelled out by Mogakolodi Ngele, who will join the Brazilians next season.
The encounter got off to a slow start with a handful of Downs supporters gathered at the far end of the stadium to spur on their side.
Most of the first-half action took place in the middle of the park with Robert Ng'ambi getting the fans on their feet in the 17th minute. The Malawian midfielder weaved his way past a number of defenders, but was unable to beat Kennedy Mweene who stood tall before making a brilliant diving save.
Sundowns had their chances in the closing stages of the first-half. Themba Zwane's snapshot kept out by Kabelo Dambe before Ramahlwe Mphahlele directed his header over the crossbar just before the interval.
Whatever Brazilians coach Pitso Mosimane said at the interval seemed to work it's magic with Mzikayise Mashaba and Bongani Zungu seeing their respective efforts cleared off the line by Dambe and Vuyo Mere before Schut's opener in the 50th minute.
The Dutch defender directed a powerful header passed a stranded Dambe from a Teko Modise free-kick.
Downs' advantage, though, would not hold with Ngele pulling Stars level after stepping off the bench. The Botswana international curled a free-kick into the top corner with 68 minutes on the clock.
Debutant Masibusane Zongo had a chance to put Dikwena ahead with five minutes of regulation time remaining. The tricky midfielder made a sniping run to the back post, but scuffed Tlou Segolela's cross with the goal at his mercy.