The Sensex gained 77 points in the opening trade on continued capital inflows by foreign funds. Expectations of positive Industrial output data for the month of January also supported the upside in stock prices. The 30-share index, which gained over 115 points in the past two sessions, rose by 77 points, or 0.44 per cent to 17,245 points in opening trade with all the sectoral indices trading in positive zone. The wide-based National Stock Exchange index Nifty also went up by 25 points, or 0.48 per cent to 5,158 points.