Certainly he has had more than a little help from his friend, BJ Watling, as the pair set about pulling New Zealand out of a jam, effectively 24 for five midway through the middle session yesterday.
Williamson and Watling, their sixth-wicket stand worth 93 and rising, went about their business by different methods.
Williamson did give two chances en route to 80, but they appear determined not to let the good work of the first test win in Christchurch be undone without a fight.
New Zealand is 253 for five, scoring at just 2 per over, and 118 ahead, but the bigger picture hovered over the final session yesterday.
With the World Cup around the corner, New Zealand wants to go in on the back of a successful series, albeit in a different format.
A Sri Lankan win, and with it the squaring of the series, does not fit that bill.
New Zealand batted an age on this ground in its second innings 11 months ago to save a test against India, and win that rubber.
A repeat, in good batting conditions, is within Williamson's scope. Sufficient support can produce a challenging fourth-innings target for the Sri Lankans.
Williamson is closing on a ninth test hundred. If he gets there, it will be his fifth in 19 test innings, spread over four opponents.
His concentration is admirable and, with watchfulness his byword, he was impressive, and luck smiled on him yesterday - dropped at 29, a return catch to spinner Rangana Herath, and at 60 when Nuwan Pradeep spilled a hook, after a couple of juggles, at fine leg off Dhammika Prasad.
He has already batted more than five hours, driving elegantly and working the ball about the field skilfully.
Watling, cutting energetically and scampering hard, is in need of a strong innings. His last of substance, an unbeaten 66 in Trinidad, was nine innings ago. He was resourceful and conscientious yesterday over just short of three hours in the middle.
New Zealand did not help its case earlier in the day.
Openers Tom Latham and Hamish Rutherford, having got set, then got out, one chasing a wide delivery, the other upper cutting straight to third man. Ross Taylor lasted seven balls and three wickets had gone for four in 30 balls. Think cats and pigeons.
Brendon McCullum and Jimmy Neesham fell lbw, both after umpiring referrals after lunch, but Sri Lanka's delight was dimmed slightly in the last two hours as the two Ws knuckled down.
But this pitch is as good as it has been for batting in the match, which must frustrate New Zealand, which could have been shutting the door on Sri Lanka's hopes with a better batting performance yesterday.''
When you bowl right areas and hit the seam most of the time, you can get rewards,'' Prasad said optimistically last night.
Minds will instead turn today to how much New Zealand must be ahead when the fourth innings starts. The ground record is Pakistan's 277 for three in 2003.
Latham thought 200 could be a tough chase. But if Kumar Sangakkara's eye is still in from Sunday, it will probably need to be some way north of that.
