The Sensex surged by over 115 points in opening trade today, extending its gains for the second straight session due to sustained buying by funds on robust capital inflow amid a firm Asian trend. The 30-share index, which had gained 113 points in the previous sessions, rose further by 115 points to 20,185 level in the first five minutes of trading. Similarly, the broad-based National Stock Exchange index Nifty rose by 28 points to 6058 points.Trade analysts said that increased buying by foreign funds and a strong start on the Japan's stock exchange mainly influenced the trading sentiment.