It was a flat and tired looking show from the Cape side, possibly as a result of their midweek extra-time cup defeat to AmaZulu.
Downs though were on top of their game and deserved winners.
Ajax had half chances early on, but Nhlanhla Vilakazi’s shot was saved by Wayne Sandilands while Terror Fanteni’s scrambled effort was cleared off the line by the impressive Clayton Daniels.
The Brazilians took the lead after 38 minutes as Elias Pelembe got in at the near post to head home Teko Modise’s corner.
The second goal came six minutes after the restart as Katlego Mphela squared the ball for Modise, who showed composure to curl the ball in at the near post from 14-yards.
Mphela made it 3-0 on the hour mark with a goal of real class as he drifted in from the left and fired in an unstoppable shot across the body of Sandilands; his first league goal in seven matches.
There never appeared to be a way back for an off-form Ajax, although Lebo Manyama wasted a great chance with 67 minutes gone when he failed to beat Sandilands when clear through on goal.
George Akpabio was also guilty of missing, getting an attempted chip all wrong with the game in injury time.
By Anthony McLennan