Sri Lanka, set a 234 run win target, threatened to level the series as Kumar Sangakkara smashed a run-a-ball 101, but were bowled out for 193 in 43.4 overs after a dramatic late collapse.
Sri Lanka, cruising home on 143 for two in the 32nd over, lost eight wickets for 50 runs after paceman Jason Gillespie broke a 65-run stand for the third wicket between Sangakkara and Mahela Jayawardene (25).
Kasprowicz took five wickets for 45 runs in nine overs and Adam Gilchrist took six catches in the innings.
Earlier, Ricky Ponting (67) and Andrew Symonds (53) had top scored for Australia, rescuing the tourists after they had slipped to 62 for three after opting to bat first.
But spinners Muttiah Muralitharan and Upul Chandana sparked a late-innings collapse, taking three wickets apiece as Australia slumped from 201 for five to 206 for nine.
Scorecard
Australia
A.Gilchrist c Sangakkara b Zoysa 14
M.Hayden c Zoysa b Vaas 15
R.Ponting lbw b Muralitharan 67
D.Martyn c Zoysa b Lokuarachchi 1
A.Symonds c Jayantha b Muralitharan 53
M.Bevan c & b Muralitharan 14
M.Clarke c Dilshan b Chandana 36
I.Harvey run out 4
B.Hogg lbw b Chandana 0
M.Kasprowicz c Sangakkara b Chandana 0
J.Gillespie not out 8
Extras (lb-3 w-11 nb-7) 21
Total (all out, 47.4 overs) 233
Fall of wickets: 1-28 2-42 3-62 4-136 5-177 6-201 7-205 8-205 9-206
Bowling: Vaas 10-0-45-1, Zoysa 8-0-40-1 (w-1 nb-2), Lokuarachchi 8-0-40-1 (w-4 nb-1), Muralitharan 10-0-44-3 (w-1), Jayasuriya 4-0-24-0, Chandana 7.4-0-37-3 (w-5, nb-4)
Sri Lanka
M.Apatapattu c Bevan b Hogg 19
S.Jayasuriya c Gilchrist b Kasprowicz 0
K.Sangakkara c Gilchrist b Kasprowicz 101
M.Jayawardene c Gilchrist b Gillespie 25
S.Jayantha c Gilchrist b Harvey 1
T.Dilshan run out 9
U.Chandana c Gilchrist b Kasprowicz 13
K.Lokuarachchi lbw Kasprowicz 18
C.Vaas c Gilchrist b Kasprowicz 0
N.Zoysa lbw b Hogg 1
M.Muralitharan not out 2
Extras: (lb-2 w-2) 4
Total (all out, 43.4 overs) 193
Fall of wickets: 1-0 2-78 3-143 4-148 5-150 6-158 7-189 8-189 9-190 10-193
Bowling: J.Gillespie 8-2-20-1, M.Kasprowicz 9-1-45-5 (w-1), I.Harvey 7-0-34-1, A.Symonds 10-1-47-0, B.Hogg 6.4-0-32-2 (w-1), M.Clarke 3-0-13-0
Result: Australia won by 40 runs.
First match: Australia won by 84 runs.
Second match: Sri Lanka won by one run.
Third match: Australia won by five wickets.
Fifth match: February 29, Colombo.
