NEW DELHI: The nightmare of facing Ravindra Jadeja on a rapidly deteriorating Eden Gardens pitch became all too real for the South African batters, as India closed in on a commanding victory by the end of the second day of the opening Test.

At stumps, South Africa were reeling at 93 for 7, leading by just 63 runs, with Jadeja running riot through the lineup. His brilliant spell of 4 for 29 in 13 overs left the visitors in deep trouble, with skipper Temba Bavuma (29 off 78 balls) fighting a lonely battle.

For the Proteas to even stretch the match into the third day - which looks poised to be the final one - they would need at least another 125 runs, a target that appears increasingly unrealistic.

The moment Jadeja entered the attack, stand-in captain Rishabh Pant - typically animated and constantly guiding Axar Patel and Kuldeep Yadav - was caught on the stump mic saying, "Jaddu bhai, aap dekh lena," a clear nod to the seasoned maestro who hardly needs instructions on such surfaces.

While Simon Harmer's classical off-spin had dragged South Africa back into the contest earlier in the day, Jadeja was always expected to be the ultimate threat on this crumbling wicket. His relentless length, stump-to-stump accuracy, and trust in the surface did the rest.

Kuldeep Yadav chipped in with 2 for 12 and Axar Patel added 1 for 30, providing Jadeja with ideal support. India's fourth spinner, Washington Sundar, has bowled just a single over across the 90 delivered by the hosts through both innings so far.

Historic Milestone! Ravindra Jadeja becomes only the fourth player to achieve rare double in Tests

Bowling at a stretch in a 13-over non stop spell from the dreaded Club House End, Jadeja's relentless accuracy on a two-paced, dust-spewing surface swung the game back India’s way in a dramatic finish to a day that saw 15 wickets to tumble (discounting Shubman Gill’s retired hurt).

Introduced in the ninth over of the innings -- the second after tea -- Jadeja struck almost immediately.

His very first ball turned sharply past Aiden Markram’s outside edge; the next one overpitched on middle, turned away, and Markram’s attempted sweep ballooned off a thick top-edge to Dhruv Jurel at short leg.

With Kuldeep Yadav having removed Ryan Rickelton (11) in the previous over with a googly, South Africa lost both openers within minutes of wiping the deficit.

Stand-in captain Rishabh Pant, taking charge after Gill’s neck spasm, backed Jadeja in a non-stop spell from the more treacherous end. The move paid off handsomely.

Wiaan Mulder (11) feathered a beauty that kissed the outside edge; two balls later Tony de Zorzi (2) was done in by a hint of turn that grazed the glove, clipped pad and looped to short leg.

Tristan Stubbs (5) misread the line and length altogether, beaten on the inside as Jadeja hit middle to claim his fourth -- also his 250th Test wicket in India, behind only Kumble, Harbhajan and Ashwin.

Axar Patel then chipped in from the High Court End, knocking over Kyle Verreynne the South Africa’s last recognised batter as the wicketkeeper-batter misfired a slog-sweep after surviving 15 balls.

Earlier in the day, Jadeja had contributed a valuable 27 with the bat, entering the elite club of Ian Botham, Kapil Dev and Daniel Vettori as only the fourth cricketer with the double of 4000 Test runs and 300 wickets.

Pitch under spotlight

What began as a slightly dry surface on Friday transformed into what resembled a fourth-day subcontinental wicket by the second hour of the morning session.

Cracks widened, puffs of dust flew on good-length balls, and bounce became alarmingly variable --conditions former India coach Ravi Shastri termed “ordinary” and ex-England captain Michael Vaughan called “awful”.

It is still not clear whether controversial Eden Gardens curator Sujan Mukherjee provided a below par Test track like this on his own volition or was pressurized by any senior member of the support staff.

KL Rahul (39 off 119) and Washington Sundar (29 off 82) had appeared resolute in the first hour, extending their compact partnership to 57 and raising hopes of a possible Indian surge.

But Simon Harmer and Keshav Maharaj’s sustained pressure post-drinks flipped the script dramatically.

Harmer opened the gates by removing Washington with a classical off-spinner’s dismissal, then saw Gill retire hurt after a slog sweep triggered a neck spasm.

Maharaj then added Rahul, whose attempt to accelerate ended with a low catch at slip as the ball turned and stayed low.

Rishabh Pant briefly counterattacked with trademark audacity, smashing Maharaj for two sixes and unfurling a reverse sweep but Corbin Bosch removed him with a sharp bouncer just before lunch.

India never recovered thereafter. Harmer finished with 4/30 from 14.2 overs, relentlessly teasing India’s six left-handers -- a first in their Test history, while tall pacer Marco Jansen (3/35) used steep bounce to clean up the lower order as India folded for 189, a slender 30-run lead.

At tea, India took the wicket of South Africa opener Ryan Rickelton with Kuldeep giving the breakthrough that made 20 wickets to fall across five sessions in the opening Test.

On a pitch where strokemaking has been near-impossible and survival itself a challenge, the final two days may not be required.

India’s spinners have already shown enough control and threat to suggest that even a chase of 120-150 could become tricky.

With the match hurtling towards a third-day finish, Sunday’s first session could well decide the series opener.

(With PTI Inputs)