The BSE benchmark Sensex extended gains for the third-straight day by adding nearly 82 points in early trade today. This follows foreign funds inflow amid a firming trend in the global markets.The 30-share barometer rose by 0.41 per cent, to 19,971 with stocks of realty, metal and IT sectors leading the gains. The index had gained over 313 points in the previous two sessions.Similarly, the wide-based National Stock Exchange index, Nifty moved up by 21.55 points to 6,065.10.Hong Kong's Hang Seng index rose by 0.72 per cent, while Japan's Nikkei up by 1.35 per cent in the early trade. The US Dow Jones Industrial Average gained 0.58 per cent to close above 15,000 for the first time in yesterday's trade as investor optimism about the US economy.