India overcame gritty resistance from South Africa's batsmen to win the fourth and final Test by a massive 337 runs in New Delhi on Monday and seal the series 3-0.

India had to work hard for victory after the world number one side resorted to hours of stubborn defensive batting, scoring at barely a run an over, in the hope of salvaging a draw.

But their plans were dashed by the equally determined Indian bowlers led by off-spinner Ravichandran Ashwin, whose 5-61 in the second innings saw him finish the series with a total of 31 wickets.

Paceman Umesh Yadav chipped in with three wickets as South Africa were bowled out for 143 soon after tea, after being set a massive target of 481.

"All wins are special but this one more so because we had to work harder for it," said Indian captain Virat Kohli.

"The South African batsmen put their heads down and were playing for a draw.

"We were surprised with how they were defending (but) our bowlers did not lose patience. They can be really proud of their effort today."

India went into the final Test with a 2-0 lead, having already won the first and third matches. The rain-hit second game ended in a draw.

India declared on 267-5 after making 334 in their first outing, thanks to man of the match Ajinkya Rahane who hit centuries in each innings.

The Proteas fought bravely in the first two sessions Monday but their innings unravelled soon after tea, as they lost their last five wickets inside 5.1 overs.

The win helped India climb two places to second in the world Test rankings.

AB de Villiers (43 off 297 balls) and skipper Hashim Amla (25) stonewalled the attack during their marathon innings but some of the other batsmen caved in without making much effort.

"You got to do what is best for the team," said Amla. "It is easy to go out there and get some runs but we tried to take it as deep as possible and get something out from this game.”

The series defeat was South Africa's first in nine years away from home.

SCORES IN BRIEF
INDIA: First innings 334
SOUTH AFRICA: First innings 121
INDIA: Second innings 267 for 5 decl
SOUTH AFRICA: Second innings 143 (Bavuma 34, Amla 25, De Villiers 43; Ashwin 5-61, Jadeja 2-26, Yadav 3-9)
Result: India won by 337 runs and clinched 4-match series 3-0.  
Player-of-the-match: Ajinkya Rahane.
Player-of-the-series: Ravichandran Ashwin.