The Mamelodi Sundowns machine - the finest team seen in the Premier Soccer League era - are Absa Premiership champions for a third time, wrapping up the title yesterday in Atteridgeville.
Mosa Lebusa's second-minute strike for Ajax was answered by Sundowns' Khama Billiat (12th), Ricardo Nascimento's penalty (29th) and Sibusiso Vilakazi (36th).
Second-placed Orlando Pirates' 1-0 defeat away against Cape Town City meant Downs became champions with a match to spare. And with a lead of seven points, they no longer need to have the Tendai Ndoro eligibility matter on their minds either.
It is Sundowns' second league title in three years, following that of 2015-16.
Sundowns will now turn their attention to repeating 2016's feat of becoming African champions and go to the Club World Cup.
Downs, trying to establish themselves as the Barcelona of Africa, deserve this title.
Last season Sundowns played 53 matches, losing their league title to Bidvest Wits and dropping out of the African Champions League in the quarterfinals.
But they recovered, and in the second half of the season - as the PSL caught fire too, with some spectacular matches and goals being scored, and Pirates laying on a challenge - they hit full throttle again.
Yesterday Sundowns had to fight to quell desperate Ajax's spirit in the first half.The Brazilians conceded a soft opener when Grant Margeman's corner was allowed to dribble through their area to Mosa Lebusa, who slotted a 1-0 lead for Ajax.
Straight away Downs found their stride. In the 10th minute a punt upfield from Sundowns' goalkeeper Denis Onyango found Percy Tau, who outstripped Ajax's Morne Nel, but then slid his finish past the upright.
Sundowns equalised as Tau left another defender - scorer Lebusa - sprawled on the right, then crossed for Billiat to volley it in at the far post.
Still Ajax fought on. An uncleared cross fell to Yannick Zakri, who slammed a volley onto Onyango's left upright.
That rattled Downs as Themba Zwane's stray pass in his half found Fagrie Lakay. Sundowns won the ball back and turned the defensive situation into a scoring one, finding Billiat alone in the area to be clattered down by Ajax goalkeeper Jody February.
Nascimento's penalty was low to the right of the Ajax goalkeeper, who got a touch, but could not stop the goal.
The Brazilians muscled the strike that would surely kill Ajax's spirit. Walking through down the left, Zwane fed Vilakazi in the middle. Vilakazi turned, fashioned space and rolled a finish past February.
That Ajax had been broken seemed verified by coach Muhsin Ertugral bringing on Samuel Julies for Isaac Nhlapo before the break to switch from three centrebacks to two.
Sundowns, after half time, were only concerned with managing the game.
And in so doing, goals could come too. Before the hour Tau forced a save from February, from successive rebounds Zwane saw a shot blocked and Billiat found the recovered keeper.
Then Downs shut down the game, and won themselves the title.
Mamelodi Sundowns (3) 3
Ajax Cape Town (1) 1
GOALS: Sundowns - Khama Billiat (12m); Ricardo Nascimento (29m); Sibusiso Vilakazi (36m); Cape Town City - Musa Lebusa (2m)...