Tony de Zorzi and Yaseen Vallie scored unbeaten centuries as Western Province dominated day one of their match against the Free State Knights at Newlands.
WP were 227-1 at stumps, with De Zorzi 104* and Vallie 119*, to lead by 116 runs.
Earlier, Beuran Hendricks took 4-16 in 9.2 overs as the Knights were dismissed for 111.
At the Wanderers, Joshua Richards struck 107 as the Central Gauteng Lions reached 251-6 against the Northerns Titans. Ryan Rickelton is 42* and Sisanda Magala 31*.
Proteas spinner Simon Harmer (6-48) took all of the wickets to fall.
Simon Harmer with 4/15 in 12 overs so far against the Lions on a Day 1 pitch at the Wanderers, including this beauty to dismiss centurion Joshua Richard#4DaySeries pic.twitter.com/efjesSNOCc
— Werner (@Werries_) November 24, 2022
Jason Smith took 5-55 as the KZN Dolphins bowled out the Boland Rocks for 211 at Kingsmead. Clyde Fortuin (93*) fought a lone battle for the visitors with the bat.
The Dolphins were 76-2 at stumps, with opener Sarel Erwee on 42*.
The EP Warriors ended the first day of their match against the North West Dragons at St George’s Park on 339-5.
Matthew Breetzke remains unbeaten on 97, while Diego Rosier scored 80 and openers Kyle Jacobs and Jordan Hermann 48 each.