Bengaluru, Nov 14 (IANS): Indian off-spinner Ravichandran Ashwin claimed a couple of crucial wickets to leave South Africa struggling at 78/3 at lunch on the opening day of the second Test being played at the Chinnaswamy Stadium here on Saturday.

Ashwin sent back opener Stiaan van Zyl and Faf du Plessis to give India the advantage. A.B. de Villiers, who is playing in his 100th Test, was at the crease with left-handed opener Dean Elgar when lunch was called. Elgar was batting on 38 with one six and a couple of boundaries.

Opting to bowl first on a moist pitch on winning the toss, Indian skipper Virat Kohli saw his decision vindicated as the Indian pacers troubled the batsmen with swing and movement off the seam.

The South African openers survived a few close calls before fast bowler Varun Aaron uprooted Hashim Amla's off-stump when the Proteas' skipper misjudged the line of a delivery that kept straight after pitching.

The introduction of Ashwin into the attack produced immediate results as he claimed two wickets in his very first over. The Chennai off-spinner struck the first blow when left-handed opener van Zyl was trapped leg bofore with a straight delivery.

He outfoxed du Plesis three balls later with Cheteshwar Pujara taking a fine low catch at forward short leg. It was initially ruled not out by the on-field umpire before the third umpire overruled the decision.