1:03 PM
Farhan
Pakistan won the toss and elected to bat at the Westpac Stadium, but were dismissed for just 124 in 37.3 overs.
And the home side cruised to their victory target with more than 32 overs to spare to take a 1-0 lead in the six-match series.
Southee took the first three wickets to fall as Pakistan slumped to 29 for three and were never able to recover.
There was plenty of help in the pitch for the home bowlers and Hamish Bennett took three for 26 after threatening to complete a hat-trick.
Mohammad Hafeez (nought) was the first man to go, Southee luring him into an edge behind to wicketkeeper Brendon McCullum, and Kamran Akmal soon followed to leave Pakistan in early trouble.
Southee claimed his third wicket in fortunate circumstances when Asad Shafiq was given out lbw, television replays showing the ball would have comfortably bounced over the stumps.
Younis Khan and Misbah-ul-Haq steadied the ship as they had done in the drawn second Test earlier this week, Younis making 24 from 35 balls before falling to Bennett.
Bennett then dismissed Umar Akmal for a golden duck but wasted his chance of a hat-trick with a terrible wide bouncer at new man Shahid Afridi.
Afridi made 15 and Misbah 50 from 88 balls before being last man out to give Southee his fifth wicket, but only three Pakistan players had made double figures in a massively sub-par total.
Any hopes of defending that total disappeared as Ryder and Martin Guptill put on 84 for the first New Zealand wicket, including 50 from the first six overs before tea.
Ryder in particular was in no mood to hang around as he hit six fours and two sixes before being caught off the bowling of Sohail Tanvir.
Guptill (40 not out) and Ross Taylor (23 not out) saw New Zealand home from just 17.2 overs and captain Daniel Vettori said: "It was a good performance, I think we bowled extremely well.
"There was probably more in the pitch than we thought. Tim Southee set it up for us with how he swung the ball. So far in this whole Pakistan series he has bowled very well."
