Full scorecard
The partnership took only 377 deliveries and the bowlers had to wait 267 agonizing minutes to separate them.
It took a special delivery with the second new ball from Ethy Mbhalati to remove Van Wyk for 133 when he edged it to second slip, where Jacques Rudolph made no mistake.
With his departure, the Knights were reduced to 318/5.
Mbhalati produced a pearl of a delivery to send Ryan McLaren back to the pavilion with the next ball, caught behind, in McLaren’s 100th first-class appearance.
Yet, in spite of Mbhalati’s double-strike, the first day belonged to the centurions, Bailey and Van Wyk.
Van Wyk’s 133 came off 188 balls, with nineteen fours and two sixes.
At stumps Bailey was undefeated on 157. He had faced 253 balls and hit 23 boundaries.
Things might have worked out differently for the defending champions if they had held on to five chances, but their inept fielding allowed Van Wyk to score his 15th first-class ton, and Bailey his seventh.
The Titans were in the driving seat in the morning session, taking three early wickets with the new ball and collecting another one midway through the first session to give them the ascendancy as the Knights slipped to 59/4.
But they dropped five catches to allow the hosts to wrestle control of the first innings from them.
Bailey was dropped on 28, 30 and 45, and Van Wyk benefited from another missed opportunity before he had opened his account.
Van Wyk hit the ball square to point and Pieter Malan dropped a regulation chance.
Roelof van der Merwe spilled a chance in the gully when Bailey was on 28. Ethy Mbhalati then moved in off the fine-leg boundary to catch Bailey when on 30, but dropped a relatively straight forward chance.
And Heino Kuhn, instead of leaving it to first slip to catch Bailey off an edge when he had 45, decided to dive in front of first slip and offer Bailey a reprieve.
Bailey and Van Wyk piled on the agony after those inexplicable fielding lapses.
They completed their century-stand off 151 balls and their double-century partnership off 293 balls in 209 minutes.
Van Wyk hit a straight four off the left-arm spinner, Van der Merwe, to reach his 15th first-class century.
Mbhalati had Aubrey Swanepoel caught by CJ de Villiers at fine leg for 16 late in the day to bolster his figures to 4/61 in 20 overs.
Rowan Richards captured 2/65 in 16 overs, and David Wiese 1/58, also in16.
The left-arm spinner, Paul Harris, finished with 0/46 in 13 overs.
Teams:
Knights: Morné van Wyk (captain), Dean Elgar, Reeza Hendricks, Obus Pienaar, Ryan Bailey, Werner Coetsee, Ryan McLaren, Aubrey Swanepoel, Malusi Siboto, Quinton Friend, Dillon du Preez
Titans: Henry Davids (captain), Jacques Rudolph, Tumelo Bodibe, Pieter Malan, Heino Kuhn, David Wiese, Paul Harris, CJ de Villiers, Ethy Mbhalati, Rowan Richards, Roelof van der Merwe.