Kolkata, Feb 17 : India tightened their grip picking up key South African wickets at regular intervals but Hashim Amla soldiered on at tea on a rain-interrupted fourth day of the second Test here Wednesday.

With skipper Graeme Smith (20), last innings' centurion Alviro Petersen (21) and the experienced Jacques Kallis (20) back into the pavilion, the visitors were 111/3, still needing 236 runs to avoid innings defeat at the Eden Gardens.

India had scored 643 for six declared in reply to the tourists' first innings total of 296 in the crucial Test which would not only decide the series but also the top slot among Test nations.

Amla (45) and Ashwell Prince (0) were occupying the crease at the Eden Gardens, where rains have already robbed 133 minutes of playing time on the penultimate day.

The start of the fourth day's play saw a 93-mintue delay due to a wet outfield following overnight showers before bad light and rain shortened the post lunch session by 40 minutes.

All the three dismissed batsmen failed to capitalise on good starts as Indian spinners Amit Mishra (2/15) and Harbhajan Singh (1/27) took the wickets extracting turn from the deteriorating pitch.

Resuming at the overnight score of 6/0, South Africa lost the prized wicket of Smith in the rain-curtailed morning session as the visitors reach 39 for one at lunch.

Mishra got rid of Smith in the penultimate over before lunch with a top spinner that beat the batsman and hit his frontpad in front of the wicket.

After lunch, Harbhajan plotted Petersen's return to the pavilion with a drifter that went off bat and pad into the hands of short leg.

Kallis and Amla then added 57 runs in 66 minutes before Mishra struck again. The leg spinner bowled a beauty of a leg-break that took Kallis' inside edge as the batsman offered a defensive shot for Mahendra Singh Dhoni to do the rest behind the wicket.

In the morning, under very overcast conditions, the umpires Ian Gould and Steve Davies carried out two inspections at 9.30 a. m. and 10 a. m. and decided on a delayed start at 10.30 a. m.

The pre-lunch period also saw medium pacer Zaheer Khan stick to a line on or outside the off stump and induced an edge from Petersen in his third over as the opener slashed at an away-going ball but V. V. S. Laxman failed to reach despite diving full stretch at second slip.

Zaheer, however, sustained an injury after bowling five overs, and could send down only one over after lunch, besides spending a long time in the dressing room.

South Africa are leading the series 1-0 after the innings win at Nagpur.(IANS)