Sri Lanka clinched second spot behind South Africa in the official rankings as they swept aside New Zealand by 96 runs in the final Test on Sunday to sweep the series 2-0.
Left-arm spinner Rangana Herath claimed five wickets as the Kiwis, set an improbable victory target of 494 runs, were bowled out for 397 in their second innings just before tea on the fifth day.
Sri Lanka had to overcome spirited batting by Kiwi captain Daniel Vettori and heavy rain during the lunch break that delayed resumption by 35 minutes to build on their 202-run win in the first Test at Galle.
Vettori hit 140, his fourth Test century, to lead a stirring fightback by the lower order after the top batsmen had failed to put up any resistance.
The left-hander frustrated the Sri Lankans for more than four hours in which he faced 189 deliveries and hit 16 boundaries, before he was last man to be dismissed.
Vettori scored 272 runs and claimed 10 wickets in the series, and in the process became only the eighth batsman in the world to achieve the double of 3,000 runs and 300 wickets.
Vettori put on 124 for the seventh wicket with Jacob Oram (56) and 69 for the ninth with Iain O'Brien, who kept his captain company at the crease for an hour and 18 minutes while making a paltry 12.
The hosts, who were joint second in the rankings with India, needed to win both Tests to claim the number two spot on their own. India are now third while Ashes losers Australia take fourth place.
The success leaves Kumar Sangakkara with four wins in five matches as Sri Lanka's captain since taking over from Mahela Jayawardene in the preceding home series against Pakistan.
New Zealand, who began the last day gasping for survival at 182-6, lost just one wicket in the morning session as they went to lunch on 302-7, the merest whiff of an unlikely upset in their nostrils.
Oram was dismissed just before the break when he drove part-time spinner Tillakaratne Dilshan uppishly to the cover region where Sangakkara took an overhead catch.
Vettori and Oram had survived a torrid spell from fast bowler Dammika Prasad, who was unlucky not to dismiss both batsmen in the space of four deliveries.
Vettori was on 32 when he edged Prasad between the first two slips, but neither fielder moved to take the catch.
Prasad hit Oram on the pads with the last ball of the over, but umpire Daryl Harper was unmoved even as television replays showed the batsman plumb in front of the wicket.
Sri Lanka suffered a minor setback before lunch when Muttiah Muralitharan limped off with a groin strain after bowling three balls of his 21st over. Thilan Thushara completed the over.
But Muralitharan, Test cricket's leading bowler, returned after lunch to have Jeetan Patel caught at short-leg for 12 and then had Vettori snapped up in the deep to signal Sri Lanka's victory.