The BSE benchmark Sensex rose by over 73 points in opening trade today, extending its gains for the third straight session despite concerns over an expected hike in key short-term rates by the RBI. The 30-share index, which had gained 435 points in the past two sessions, moved up further by 73 points, or 0.38 per cent, to 18,945 points. In a similar fashion, the wide-based National Stock Exchange Nifty index gained 22 points, or 0.38 per cent, to trade at 5,702 points. In the Asian region, Hong Kong's Hang Seng was up 1.01 per cent, while Japan's Nikkei gained 0.60 per cent in morning trade today.