Mumbai: India beat Sri Lanka by an innings and 24 runs in Mumbai to achieve the coveted number one ranking among Test playing nations.
Sri Lanka, trailing by 333 runs in the first innings, were shot out for 309 in their second knock 35 minutes into the fifth day's play at the Brabourne stadium.
The 2-0 series win lifted India to the top of the official Test rankings with 124 rating points, two more than previous leaders South Africa.
Sri Lanka slipped from second place to fourth with 115 points, one behind Australia.
Earlier on fourth day, the visitors were struggling at 274 for six on the penultimate day which was marked by Sangakkara's resilient unbeaten 133 under immense pressure.
Sri Lankan captain Sangakkara notched up his 21st Test century, his maiden one in India, to anchor the innings brilliantly but none of the other top order batsmen could stitch a substantial partnership with him to save the visitors.
The Sri Lankan captain, who had never scored even a half century in India, began cautiously but played some delightful strokes at the fag end of the day.
Resuming at the overnight score of 11 for no loss, the Lankans needed a solid start from their openers but that did not happen.
The home team struck a major blow in the ninth over when Dilshan (16) was sent back through a dubious umpiring decision.
In the first innings, Nigel Long was the umpire who declared Dilshan out caught at short leg, again off Harbhajan, when the ball seemed to have gone off his pads without touching the bat.
It also brought together two left-handers Paranavitana and Sangakkara to the crease who remained unconquered at the lunch break.
The second wicket duo eschewed risks so the scoring rate fell to under three an over and the first hour's play realised only 37 runs in 14 overs.
Sangakkara and Paranavitana raised the 50 of the innings in the 19th over and after 81 minutes of play since last evening.
Sreesanth got the first break for the home team after lunch by sending back opener Paranavitana in his first over of a fresh spell as Lanka slumped from 119 for one to 137 for four.
Zaheer, brought back for a new spell from the Churchgate end, sent back Mahela Jayawardene (12) and Thilan Samaraweera (0) in the space of 15 balls for one run.
And just as the visitors were hoping to go into tea without further loss, Ojha turned a ball across the face of all rounder Angelo Mathews' bat and India skipper Mahendra Singh Dhoni accepted the edge.
Sreesanth and Zaheer delivered the blows in the very first overs of their new spells in the post-lunch period to send back Paranavitana and former Lanka skipper Mahela Jayawardene respectively.
Sreesanth, getting some reverse-swing, brought a ball back into Paranavitana who injudiciously tried to play it to leg and was trapped plumb in front after striking eight fours in 144 balls. His partnership with Sangakkara was worth 90 in 220 balls.
Sangakkara and Jayawardene, who scored 275 in the opening drawn Test at Ahmedabad, forged together a stand of 16 runs before India struck three quick blows to bring the visitors on to their knees.
Zaheer sent back Mahela when the batsman poked at a ball that moved away a shade and edged behind the wicket for Dhoni to take an easy catch.
Then the left-arm pacer induced an edge from Samaraweera (0) which was caught at second slip by Venkatasai Laxman to leave Lanka tottering at 137 for four.
Ojha then struck another blow by having Mathews caught at the wicket.
Brief scores
Sri Lanka: 393 (Dilshan 109, Mathews 99, Harbhajan 4-112) and 309 (Sangakkara 137, Paranavitana 54, Zaheer 5-72)
India: 726 for 9 dec (Sehwag 293, Dhoni 100*, Dravid 74, Laxman 62, Tendulkar 52)
Results: India won by an innings and 24 runs
MOM: V Sehwag (India)
Man of Series: V Sehwag (India)