Durban - Stephen Cook scored his fifth hundred of the domestic four-day season to all but seal the title for the Highveld Lions, as the Dolphins were batted out of a must-win game on the third day at Kingsmead in Durban on Saturday.
Cook returned to the top of the run-scoring charts and ended the day unbeaten on 143 in a Lions total of 246 for two, which gave the visitors an overall lead of 361.
The Lions skipper will now have to decide whether to declare overnight and push for the win, or bat further knowing that a draw would just about seal the trophy anyway with one more match to play.
Should the Lions lift the trophy, Cook's runs will have played a major part - he currently has 889 of them from nine matches at an average of 74.
The only real satisfaction for the Dolphins came near the start of the day when they stretched out their last two wickets, moving from an overnight 229 for eight to 280 all out.
That owed everything to Daryn Smit's unbeaten 60 and Craig Alexander's 36, but it still left the hosts 115 runs short on the first innings.
The Lions set about adding to their advantage in some style, as Cook and Rassie van der Dussen put on 177 for the first wicket to effectively make the game safe.
Van der Dussen scored 78 before he was caught at square-leg off the bowling of Smit, and five overs later Dominic Hendricks was caught behind off the bowling of Craig Alexander.
The Lions' safety-first mentality was clear thereafter, with Neil McKenzie scoring 17 not out from 70 deliveries as he and Cook scored at barely more than two runs per over in the final part of the day - in spite of their healthy lead.