Tim Southee bowled New Zealand back into contention in the first Test against England with a dramatic burst late on the third day at Lord's on Saturday.
At stumps, England were 180 for six in their second innings -- a lead of 205 runs.
England were building a sound position at 159 for two when paceman Southee wrested back the initiative with three wickets for four runs in 17 balls.
In all, England lost four wickets for 12 runs to throw the first of this two-Test series wide open, although their lead was now almost as much as New Zealand's meagre first innings 207.
Nightwatchman Steven Finn was six not out and Ian Bell nought not out at stumps.
"Now we're into the bowlers," Southee, who had close of play figures of three for 34 in 14 overs, told reporters.
"Finn is in and we know (Stuart) Broad is capable with the bat and (Graeme) Swann is dangerous, he can score some quick runs. We can't get too far ahead of ourselves. We've still got a job to do."
Jonathan Trott (56) and Joe Root (71) shared a third-wicket stand of 123 before the latter's exit sparked England's slump.
They had steadied the ship after England captain Alastair Cook and fellow opener Nick Compton had fallen to the left-arm pace duo of Trent Boult and Neil Wagner respectively with the score on 36.
Shortly after tea, Root was nearly run out when he dabbed the ball onto the offside and set off for a single before Trott sent him back.
A direct hit by New Zealand captain Brendon McCullum would have seen the Yorkshireman run out but Root just did enough as wicket-keeper BJ Watling tried to make the best of a bad return with a despairing effort of his own.
Watling injured his knee in the process and was replaced behind the stumps by McCullum, who had given up keeping in Tests because of knee and back problems.
Root, in only his fifth Test and first in England, punched Wagner through the covers for four to complete a 78-ball fifty featuring six boundaries.
But in sight of beating the Test-best 73 he made against India on debut in Nagpur in December, the 22-year-old, promoted up the order because Bell had flu, inside-edged Southee on to his stumps.
Root's Yorkshire colleague Jonny Bairstow, top-scorer in England's first innings with 41, was then yorked off his foot by Southee for five.
The collapse continued when wicket-keeper Matt Prior, so often England's saviour with the bat, completed a pair when he pulled Southee to square leg.
Trott then exited when he was bowled by a sharply turning off-break from part-time spinner Kane Williamson.
It was a worrying sight too for New Zealand's batsmen, with England having the fit-again Swann, one of the world's leading off-spinners, in their side.
"Trott and Root were making it look very easy so it was nice to get back in the match," Williamson, who earlier made 60, told Sky Sports.
"It's going to be a big challenge for us to come back tomorrow (Sunday) and take the last four wickets and then chase the total because it's suiting the bowlers."
Williamson's view was backed by Root, who said: "It's quite a slow pitch -- you've got really work hard to start with. I was very disappointed not to kick on and, after giving them a sniff tonight, we're quite down about it.
"Hopefully we can have a good morning and build a platform to win the game."
Before lunch, England dismissed New Zealand for a first innings lead of 25.
James Anderson, who on Friday had become only the fourth England bowler to take 300 Test wickets, finished with five wickets for 47 runs in 24 overs.
It was the 30-year-old Lancashire swing bowler's 13th five-wicket or better innings return in an 81 Test-career that started at Lord's a decade ago.
He was well supported by Finn (four for 63) although it was fellow seamer Broad who had dangerman McCullum caught behind for just two early Saturday.