The Downs’ goals were scored by Papi Zothwane and a brace by Katlego Mphela. Wits were down to 10-men in the first-half when Thando Mngomeni was sent off.
Overall it was a convincing a solid showing by Downs and put to an end a run of a couple of unsatisfactory results.
Downs announced their intensions early on when Katlego Mphela headed home a 10th minute corner, 1-0.
The Brazilians doubled their lead in the 31st minute when Mphela converted from the spot, sending Darren Keet the wrong way.
The spot kick had been awarded after an intricate move around the box ended with Richard Henyekane bursting goal-wards before he was abruptly and illegally halted by Sipho Mngomezulu.
Thando Mngomeni saw it fit to argue Mngomezulu’s case and was dismissed for his over-enthusiastic comments to the referee.
Downs added a third goal after 41 minutes when Papi Zothwane tapped in from close range after Mphela had struck the upright.
Sundowns were able to take their foot off the pedal for the second half with the victory all but secured after their highly impressive first half showing, which saw the Pretoria side full of running in attack, solid and the back and dominant in the middle of the park.
The Clever Boys could perhaps have pulled one back on the hour mark, but Mark Haskins’ shot from 14-yards out was too close to Wayne Sandilands.
Teko Modise, on as a second half sub, was unable to really stamp his authority on the game and missed a decent chance when he shot over the bar after a scintillating 78th minute move involving several players.
In the final minutes the Brazilians were pretty much able to go through the motions as they ran down the clock against a Wits side that suffered their first defeat for six matches.