The Sensex recovered by over 40 points in the opening trade today on revival of selective buying by funds after late selling yesterday. Major support to the market came in from the auto, oil and gas, banking and metal sector stocks. The 30-share index, which had lost 48 points in yesterday's volatile session, rose by 40 points or 0.22 per cent to 17,978 points in the opening trade. The wide-based National Stock Exchange's Nifty rose by 13.05 points, or 0.24 per cent, to 5,399 points.