An unbeaten century by Zubayr Hamza helped the log-leading Cape Cobras seize the advantage after two days of their decisive four-day domestic series encounter against the Dolphins in Pietermaritzburg on Tuesday.
The right-hander, who made his Test debut for South Africa against Pakistan earlier this month, was still batting on 104 (207 balls, 12 fours) and his side on 245/3 when bad light ended play early at the City Oval.
By that stage, the visitors trailed by just 65 runs in what is their final match of the first-class season.
The Cape side held a lead of just over three points heading into the fixture and they are bidding to hold off the Highveld Lions, who are playing the Warriors in their last game.
And Ashwell Prince’s side enjoyed a perfect day two, which began brightly through a brilliant Vernon Philander burst that put them on the front foot right from the outset.
The South Africa seamer nabbed four wickets without conceding a run in 14 deliveries on the second morning as the hosts slipped from 293/6 overnight to 310 all out.
It gave him figures of 4/46 in 14.2 overs, with George Linde (4/62) also finishing with four wickets.
It was then over to the batsmen to fire, and led by Hamza, they did not disappoint.
Simon Khomari (14) put on 29 with the in-form Pieter Malan (44) for the first wicket, with the latter then adding 68 with the centurion for the second wicket.
A further 64 followed for the third wicket between David Bedingham (37) and Hamza, who went on to complete his 10th first-class century.
He was still there at the end sharing another useful stand of 84 unbroken with Kyle Verreynne (41 not out).