Wits scored first and last, but between those two goals Dikwena carved their opponents open at will.
The visitors took the lead just after the break through Ryan Chapman, but from then on in it was all Dikwena as they netted through Siphelele Mthembu (two), Mogakolodi Ngele and Henrico Botes.
Getaneh Kebede gave Wits some hope for the second leg on September 24 with a late goal.
Faty Papy had two great headed chances in the first half, but could not convert with either, while Ngele struck the crossbar and Mthembu wasted the rebound.
The deadlock was finally broken on 48 minutes as Chapman took advantage of the Stars defence backing away from him and blasted the ball home with a low shot.
Stars equalised on 56 minutes when Mthembu split the centre-backs with his run and fired the ball past a helpless Moeneeb Josephs.
Wits seemed shell-shocked and they fell behind seven minutes later as Ngele beat the offside trap and scored.
The third goal came on 72 minutes through an error from Tinashe Nengomasha.
The veteran Zimbabwean midfielder was attempting to clear in his own penalty-box, but stood on the ball and fell to the ground, allowing Mthembu a clear run on goal to score.
And it was 4-1 three minutes later as the ponderous Wits defence were split open again. Ngele played a delightful ball to vuyo Mere on the right and he slipped in Botes behind the defence. The Namibian international’s low finish past Josephs was clinical.
Wits gave themselves some hope with a goal eight minutes from time. Matthew Booth had been deployed up-field to use his height and his low centre ball was back-heeled into the net by Ethiopian star Kebede.
The second leg will be on September 24 at Bidvest Stadium, with a 7.30pm kick-off.