NEW DELHI - Skipper Virat Kohli led from the front with an unbeaten 83 as India gained a stranglehold on South Africa in the fourth and final Test on Saturday.

At stumps, the hosts were 190-4 for a formidable lead of 403 with six wickets in hand. Kohli smashed 10 fours in his composed 154-ball knock and shared 133 runs for the unbroken fifth wicket with first-innings centurion Ajinkya Rahane (52) to pull India out from a shaky 57-4.

The fiery Indian skipper, 27, completed his 12th Test half-century in the process, delighting a sizeable home crowd at the Feroz Shah Kotla stadium in New Delhi. India, who have already sealed the series with wins in the first and third Tests, had bowled out the top-ranked tourists for 121 after making 334 for a first-innings lead of 213 runs.

Kohli's stand with Rahane, who top-scored with 127 in his first outing, was the first century-stand of what had been a low-scoring series so far. With the Kotla pitch likely to deteriorate on the fourth and fifth days, it will be an uphill task for the Proteas to breach India's run wall.

The visitors have been bowled out under 200 five times out of six innings in the series. "The way we batted in the first innings has put us in a good position," said Ravindra Jadeja, who took a five-wicket haul in the first innings. "They could not bat well in the first innings and we got a big margin of 213 runs. This made the big difference."

Paceman Morne Morkel was the most impressive bowler on show, taking three wickets while giving away just 29 runs from 17 overs. After picking two scalps in the morning, Morkel returned to dismiss Shikhar Dhawan with a stinging yorker from around the wicket that sneaked under the bat and hit the leg stump.

"I think the yorker was a bit of an out of the box thing, a kind of spur of the moment," said Morkel's pace partner Kyle Abbott. "Sometimes you have got to do that in these situations when pitches are not helping you much. You've got to make the most of what you have got.... He (Morkel) has been the standout bowler for us this whole series."

Dhawan, celebrating his 30th birthday Saturday, played an unusually sedate knock, facing 86 balls to make 21. Cheteshwar Pujara (28) was castled by Imran Tahir soon after but the bowlers were denied any further success by the determined pair of Kohli and Rahane.

Kohli risked being fined for showing dissent to the umpire when he angrily stood his ground, hands on hips, to show his displeasure when he was given out caught behind off Tahir. The Indian skipper, on five then, was lucky to have the decision reversed as TV replays showed Tahir had overstepped.

The Indians were off to a wobbly start in their second knock, losing two wickets with just eight runs on the board. Opener Murali Vijay (three) was given out to a rising ball from Morkel that appeared to have grazed his armguard before flying through to wicketkeeper Dane Vilas, who leapt high in the air to take a one-handed catch over his head.

Vijay looked displeased with the decision, shaking his head as he walked off the ground. Morkel struck again with the first ball of his next over to dismiss the struggling Rohit Sharma for a golden duck, the ball zipping past his bat and flattening the off-stump. Sharma's best score in the series has been a 23 in Nagpur, raising doubts about his temperament in the longest form of the game.

Scoreboard

INDIA 1ST INNINGS: 334

SOUTH AFRICA 1ST INNINGS: 121

INDIA 2ND INNINGS:

M Vijay c Vilas b Morkel 3

S Dhawan b Morkel 21

R Sharma b Morkel 0

C Pujara b Tahir 28

V Kohli not out 83

A Rahane not out 52

EXTRAS: (lb2, nb1) 3

TOTAL: (for 4 wkts, 81 overs) 190

FOW: 1-4, 2-8, 3-53, 4-57

BOWLING: Morkel 17-6-29-3, Abbott 17-6-38-0, Piedt 18-1-53-0, Tahir 21-4-49-1 (nb1), Elgar 8-1-19-0

TOSS: India

UMPIRES: Kumar Dharmasena (SRI) and Bruce Oxenford (AUS)

TV UMPIRE: C.K. Nandan (IND)

MATCH REFEREE: Jeff Crowe (NZL)