New Zealand assumed control of the second and final Test against Sri Lanka as Kane Williamson and BJ Watling compiled a world record sixth-wicket partnership in Wellington.
Williamson and Watling put on 365 as the Blacks Caps declared on 524 for five, setting the tourists a target of 390 in just over three sessions.
Williamson was undefeated on 242 off 438 balls while Watling was 142 not out from 333 deliveries, both international-bests.
Sri Lanka then reached 45 for one by the close, still needing to bat out all three sessions on the final day to avoid defeat.
Williamson and Watling's alliance was worth 94 when they strode out to the middle at the Basin Reserve this morning and Watling brought up his fifty in just the third over of the day.
The century partnership soon followed, and Williamson and Watling were looking reasonably comfortable in the middle as they built New Zealand's lead.
The runs were not flowing easily, though, and when Williamson reached his ton it had taken him 243 balls before he was dropped for the third time in the match when Prasanna Jayawardene put him down on 104 off Rangana Herath.
And once again Sri Lanka were punished by the 24-year-old as he brought up his 150 and the 200 partnership after lunch with a swept boundary off Herath.
When the stand reached 247, Williamson and Watling had New Zealand's highest sixth-wicket alliance against Sri Lanka, overtaking the previous best compiled by Jeff Crowe and Sir Richard Hadlee.
Watling brought up his century off 270 balls in the following over and Sri Lanka were looking seriously short of ideas as the hosts began to establish a strong grip on the game that would have looked unlikely on day three.
The lead was 310 at tea as an evening declaration suddenly began to loom large as Williamson brought up his first Test double-century with a boundary off Herath taking the partnership to 300 in the process.
Watling soon followed Williamson to his own highest Test score and the wicketkeeper helped Williamson guide the partnership past the world-record 352 that he and Brendon McCullum had shared for a sixth-wicket against India - also in Wellington - in February last year.
McCullum eventually called an end to the innings, and made Sri Lanka face an awkward 17 overs before the close, with Dimuth Karunaratne the wicket to fall as he paddled a Mark Craig delivery to Hamish Rutherford.
Well played Kane Williamson 242* & sharing a world record sixth-wicket partnership of 365 with BJ Watling @BLACKCAPSpic.twitter.com/QmtTf9GdOU
— Yorkshire CCC (@Yorkshireccc) January 6, 2015