Nagpur, Oct 1 Rohit Sharma struck a century as India beat Australia by seven wickets in the fifth and final One-Day International (ODI) at the Vidarbha Cricket Association Ground here on Sunday to end the five-match series on a winning note. India have thus won the series 4-1. The victory also helped India regain the top spot in the ODI rankings, pushing South Africa to the second position. Australia remain third. Chasing a modest target of 243 runs, India crossed the line with 43 balls still to go. Sharma and fellow opener Ajinkya Rahane put on a 124-run partnership in 22.3 overs which virtually sealed the match in India's favour. Sharma plundered 125 runs off 109 balls with hios knock featuring 11 impressive boundaries and five hits over the fence. Rahane played a steady knock of 61 runs off 74 balls which included seven boundaries. Earlier, the Indian bowlers put in a disciplined performance to restrict the visitors to 242/9. In-form opener David Warner was the highest scorer for Australia with 53 runs off 62 balls.