The benchmark BSE Sensex gained 94 points to 20,753 in early trade today on emergence of buying by funds at existing levels amid a firming Asian trend. Similarly, the wide-based National Stock Exchange index Nifty moved up by 27 points to 6,182.In the Asian region, Japan's Nikkei spurted by 1.01 per cent, while Hong Kong's Hang Seng index gained 0.72 per cent in early trade.The US Dow Jones Industrial Average ended 0.82 per cent higher in yesterday's trade.The rupee weakened by 15 paise to 61 rupees 88 paise against the US dollar in early trade today on the Interbank Foreign Exchange market due to appreciation of the American unit against other currencies overseas. The rupee had gained 39 paise to close at 61.73 against the dollar in yesterday's trade.