Mumbai: The Bombay Stock Exchange benchmark Sensex today surged by over 204 points in opening trade, extending its winning streak for the third straight session on continued buying by funds, driven by firming trends in global markets. The 30-share index, which had rallied nearly 645 points in the previous two sessions, shot up by 204.70 points, or 1.21 per cent, to 16,871.10 points in opening trade, with all sectoral indices trading in the positive zone with gains up to 2.18 per cent.The chart showing the 52 week performance of Sensex is on the left. The wide-based National Stock Exchange index Nifty also rose by 58.50 points, or 1.16 per cent, to 5,061.60 points. Stockbrokers said the trading sentiment remained firm on the back of a rebound in global markets on easing concerns about the euro after China's assurance that Europe remains a key investment market for its foreign exchange reserves.