GALLE: Rangana Herath exposed New Zealand's weakness against spin with a six-wicket haul as Sri Lanka raced to an emphatic 10-wicket win on the third day of the opening Test in Galle on Monday.

The left-arm spinner finished with 6-43 off 18 probing overs as New Zealand, trailing by 26 runs, crashed to 118 in their second innings after losing their last nine wickets for 83.

Sri Lanka effortlessly chased down a 93-run target, with debutant Dimuth Karunaratne remaining unbeaten on 60 and Tharanga Paranavitana 31 not out.

Karunaratne, who failed to open his account in the first innings, made amends with a 60-ball knock which included nine fours.

Man-of-the-match Herath, who took 5-65 in the first innings, finished the Test with 11-108, his second haul of 10 or more wickets in a match.

Middle-order batsman Daniel Flynn, who made a half-century in the first innings, top-scored with 20 in a dismal New Zealand batting performance on a slow turning track.

It was New Zealand's fifth successive Test defeat this year after they lost two matches each in the West Indies and India.

“Rangana knows what he is doing with the ball and he knows what the batsman is doing as well,” said his skipper Mahela Jayawardene.

“After Murali (Muttiah Muralitharan), from what I've seen in Sri Lankan cricket, he is the next best thing. Others have chipped in but Rangana has become the leading bowler for us.

“Because of the pressure he is creating on the opposition and the way he's performed, it has enabled us to be consistent in Test cricket in the last two years or so.”

The Test was evenly poised at stumps on Sunday when New Zealand were nine runs ahead with as many wickets in hand, but Herath swung the match in his team's favour with four quick wickets in the morning.

“Herath dominated our batting line-up in both innings. He is a very good bowler at the moment and the leading wicket-taker in 2012,” said New Zealand skipper Ross Taylor.

“He is very consistent in this part of the world and we have got to come up with a way of negating his wicket-taking ability. We have to pick ourselves up and give ourselves a chance in the next match.”

Herath continually tested the batsmen with his shrewd variations, removing Taylor (18), James Franklin (two) and then Flynn and Doug Bracewell off successive deliveries. He was well supported by paceman Nuwan Kulasekara and off-spinner Suraj Randiv, who bagged two wickets apiece.

New Zealand's batting woes began against pace, when Kulasekara struck twice in his opening three overs, dismissing overnight batsmen Martin Guptill in his second over and Kane Williamson to have the tourists struggling at 46-3.

Williamson was caught down the leg-side by a diving wicketkeeper Prasanna Jayawardene.

Sri Lanka were bowled out for 247 in their first innings on Sunday in reply to New Zealand's 221, with Mahela Jayawardene scoring 91 and vice-captain Angelo Mathews 79.

The second and final Test starts in Colombo on Sunday.