Two subs called in as India circle series sweep

South Africa's opening batsman Dean Elgar was diagnosed with a concussion and subbed out of the third Test against India after he suffered a blow to the head on Monday.

Elgar misjudged a bouncer from fast bowler Umesh Yadav and failed to duck in time as the ball crashed into his helmet above the ear, forcing the dazed 32-year-old to retire hurt.

Theunis de Bruyn was named as a concussion substitute under new ICC rules and the 27-year-old was unbeaten on 30 at stumps, with the Proteas floundering on 8-132, still 203 runs behind India after being asked to follow on.

It’s the third time a concussion substitute has been used in Test cricket following the introduction of the new rule earlier this year. Marnus Labuschagne replaced Steve Smith during the second Ashes at Lord’s in August to become Test cricket’s first concussion sub, while Jermaine Blackwood replaced Darren Bravo during a Test against India in Jamaica last month.

Elgar will not be allowed to return to action for at least six days, the team's management said.

"The opening batsman will be closely monitored over the next 24 hours, followed by reassessment every 24 hours until signs and symptoms resolve," the South African team said in a statement.

"The soonest he can return to play is in six days' time in keeping with the standard concussion management protocol."

India also took advantage of a recent rule change, bringing in substitute fielder Rishabh Pant to keep wickets after regular gloveman Wriddhiman Saha sustained a finger injury in the final session. Up until 2017, substitute fielders were not permitted to take the gloves, but umpires are now told to use their discretion and allow it in the case of an injury.

India lead the three-match series 2-0 and, with two days left in the Test, Virat Kohli's side need two wickets to clinch a series whitewash and consolidate their place on top of the World Test Championship table.

Replying to India's 9(dec)-497, South Africa were all out for 162, conceding a massive first-innings lead of 335 runs.

Asked to follow on, they were equally poor second time around and barely avoided defeat inside three days.

Earlier, Zubayr Hamza (62) scored his maiden Test fifty in an otherwise disappointing batting performance by South Africa, who resumed day three on a precarious 2-9.

It got worse for the Proteas as they lost skipper Faf du Plessis in the first over to a beautiful delivery by Yadav.

Hamza added 91 runs with Temba Bavuma (32) but apart from them and George Linde (37), no other South African batsman reached double figures.

In their second innings, South Africa were jolted early by Yadav who bowled Quinton de Kock for five before Mohammed Shami ran through the top order with a three-wicket burst.

The right-arm quick bowler bowled Hamza for a duck, trapped Du Plessis lbw and had Bavuma caught behind to tighten the noose around the tourists.

For the visitors, only Linde, who made 27 before being run out, will emerge from his Test debut with head held high, having resisted with the bat in both innings as well as taking four wickets.