VISAKHAPATNAM – Rohit Sharma smashed an unbeaten century in his new role as a Test opener as India reached 202 without loss on a rain-hit opening day of their home series against South Africa on Wednesday.Sharma – a star of India’s limited-overs side – was at the crease on 115 with Mayank Agarwal on 84 after the hosts elected to bat in the first of the three Tests in Visakhapatnam.A sudden thunder storm forced the umpires to call tea seven minutes early and no further play was possible after heavy rains lashed the coastal city.Sharma completed his fourth Test century in the second session with a single off debutant spinner Senuran Muthusamy to raucous cheers from the home crowd and the dressing room.He hit five sixes and 12 fours from 174 balls and showed frequent glimpses of the form that has made him a feared one-day batsman.Agarwal, like Sharma, also used his feet to good effect against the South African spinners who struggled on the batting-friendly pitch.Agarwal, playing his fifth Test since making his debut last year, raised his fourth half-century with a six off lead spinner Keshav Maharaj.Both Sharma and Agarwal, who hit 11 fours and two sixes, took apart the opposition bowling in the second session of play as India scored 111 runs after taking lunch at 91-0.Sharma, who got to his 50 before lunch, shifted gears and went after the slow bowlers as he hammered off-spinner Danie Piedt for two successive sixes to move into the nineties.South Africa captain Faf du Plessis rotated his spinners for a large part of the day with intermittent spells from pacemen Kagiso Rabada and Vernon Philander.Philander, who got Sharma out for a two-ball duck in a practice game last week, tested the senior batsman early on in the innings by swinging the ball both ways.Sharma got off the mark as an opener in the longer format in style as drove Rabada for a boundary at backward point.India, who top the Test World Championship rankings, are looking for a record 11th Test series win at home in the three matches.