The Dolphins won the toss and elected to bat first, but were off to a shaky start as Andrew Birch took two early wickets that reduced them to 102 for four shortly after lunch.
But Chetty and captain Van Wyk then combined to add 144 for the fifth wicket, before Chetty fell to the off-spin of Simon Harmer, the best of the Warriors bowlers, for a fine 120 that showcased the 22-year-old's talent.
Van Wyk went on to bat through the rest of the innings, finishing with 104 not out as Harmer and seamer Rusty Theron worked through the Dolphins lower-order, bowling them out on the stroke of stumps.
Harmer was the most successful of the Warriors bowlers with four for 85 in 24.3 overs, while the pacemen - Birch, Basheer Walters and Theron -each finished with two wickets.
At Boland Park in Paarl, the Cape Cobras gained the upper hand late in the day against the Titans, as Yaseen Vallie and Dane Vilas added 145 for the fifth wicket to take the home side to 345 for five at stumps.
Vallie and Vilas provided the best batting of the day as they blunted a Titans comeback with the ball which had seen the Cobras slip to 189 for four after winning the toss and electing to bat.
The left-arm swing bowling of young Vincent Moore sparked the comeback as he claimed the wickets of Andrew Puttick (9), Justin Ontong (21) and Stiaan van Zyl (71).
But he lacked support in the final session, with Junior Dala, on loan from the Highveld Lions, the obvious weak link in the attack as he conceded 103 runs in 17 wicket-less and maiden-less overs.
The Cobras shrugged off the early loss of Puttick, caught behind off Moore, with a second-wicket stand of 114 between Omphile Ramela (59) and Van Zyl.
The left-hander needed 142 balls for his 71 and struck seven fours, taking him past 600 runs in the 2013/14 campaign, at an average of 65.60.
The 23-year-old Vallie took the fight to the Titans in a composed innings which showed impressive shot-selection.
His 80 and the return to form of wicketkeeper/batsman Vilas, who ended the day on 62 not out ensured the Cobras finished the first day in control.
The first day of the match between the Highveld Lions and the Knights at the Wanderers was abandoned due to the pitch being too wet for play after the recent torrential rain in Gauteng.