Centurion, Dec 26 : India openers KL Rahul and Mayank Agarwal justified captain Virat Kohli's decision to bat first with a careful yet solid opening stand as India reached 83/0 in 28 overs at lunch on day one of the first Test against South Africa at SuperSport Park. In the first hour of the session, South Africa employed four pace options in Kagiso Rabada, Lungi Ngidi, Wiaan Mulder and debutant Marco Jansen in helpful conditions. But none of them were able to put KL Rahul and Mayank Agarwal in trouble. Rahul was extremely compact with his leaves to anything coming wide while Agarwal fetched India's first boundary with a square drive off Lungi Ngidi. Five overs later, Rahul got his first boundary with a straight-bat drive past mid-off off Rabada. Jansen, coming in as the first-change bowler of the day, got hit for three boundaries in his first over as Agarwal drove him through the off-side while flicking him twice through mid-wicket. In the second hour of the session, Jansen came under further attack from Agarwal as the right-hander smashed successive boundaries on both sides of the wicket. On the next ball, Agarwal was dropped on 36 by keeper Quinton de Kock, thus spoiling South Africa's first genuine chance of getting a breakthrough. The Karnataka duo complemented each other by capitalising on South Africa's errors with line and length to bring India's seventh fifty-plus opening partnership in overseas Tests this year. By the end of the session, South Africa were left to rue the dropped catch by de Kock as Rahul and Agarwal carried India to lunch in a very strong position. Brief Scores: India 83/0 in 28 overs (Mayank Agarwal 46 not out, KL Rahul 29 not out) vs South Africa. /IANS