The veteran left-hander, who made 88 off 44 balls against Kenya on Friday, blasted 61 off 44 as Sri Lanka surpassed Kiwis 164-7 with seven balls to spare at the Wanderers.
Jayasuriya, the eldest player in the 12-nation event aged 38, gave his team a flying start by posting 82 for the first wicket with Upul Tharanga (37) off only 45 balls.
Jayasuriya, who hit six boundaries and three sixes, fell in the 18th over with just seven needed for victory and was named man of the match for the second day in a row.
Sri Lankan captain Mahela Jayawardene followed his 65 against Kenya with 35 not out off 18 balls with four boundaries and a six.
It was the perfect practice match for Sri Lanka, who begin their Super Eights campaign against Asian rivals Pakistan here on Monday.
New Zealand, who have also qualified for the next round from group C at the expense of Kenya, clash with India at the same venue on Sunday.
New Zealand’s innings revolved around Ross Taylor’s 62 off 44 balls after captain Daniel Vettori won the toss and elected to take first strike.
Jacob Oram remained unbeaten on 33 off 19 balls as the Kiwis hit 46 runs in the last five overs.
Dilhara Fernando claimed 2-40, but left-armer Gayan Wijekoon was hammered for 50 runs in his four overs to allow New Zealand to set a 8.5-run target.
New Zealand lost openers Brendon McCullum and Lou Vincent to fast bowler Fernando by the sixth over with the total at 25.
Taylor and Peter Fulton revived the innings by smashing 70 runs off 37 balls for the third wicket to lift the Kiwis to 95 for two.
Sri Lanka hit back with three wickets in the space of seven runs as Fulton holed out against Wijekoon, Scott Styris was trapped leg-before by Jayasuriya and Craig McMillan ran himself out. Oram helped Taylor add 51 off 36 balls for the sixth wicket.
Scoreboard
New Zealand
L Vincent c Silva b Fernando 14
B.B. McCullum c Malinga b Fernando 10
P.G. Fulton c Malinga b Wijekoon 25
R.L. Taylor c Sangakkara b Malinga 62
S..B. Styris lbw b Jayasuriya 2
C.D. McMillan run out (Silva/Malinga) 2
J.D.P. Oram not out 33
D.L Vettori run out (Fernando/Wijekoon) 3
EXTRAS: (B-1, B-2, W-10) 13
TOTAL: (for seven wkts) 164
FALL OF WKTS: 1-22, 2-25, 3-95, 4-97, 5-102, 6-153, 7-164
BOWLING: Vaas 4-0-27-0; Fernando 4-0-31-2(W1); Jayasuriya 4-0-25-1 ; Wijekoon 4-0-50-1(W2); Malinga 4-0-28-1(W1)
SRI LANKA
W.U.Tharanga c Martin b Vettori 37
S.T.Jayasuriya c Fulton b Vettori 61
K.C.Sangakkara c Taylor b Styris 14
D.P.M.D.Jayawardene not out 35
L.P.C.Silva not out 9
EXTRAS: (B-3, LB-8, W-1) 12
TOTAL: (for three wkts; 18.5 overs) 168
FALL OF WKTS: 1-82, 2-108, 3-158
BOWLING: Bond 4-0-45-0; Martin 3-0-23-0; Gillespie 2.5-0-29-0-10.23 (1w); Vettori 4-0-23-2; Styris 3-0-16-1; Oram 2-0-21-0.—AFP