Sensex and Nifty posted strong gains on September 7 after a tepid start during the day. The former closed at 66,265.56 after increasing by 385 points or 0.58 per cent. Nifty50 surged by 116 points or 0.59 per cent to close at 19,727.05. Meanwhile, US markets fell on Wednesday as Apple stocks faced pressure due to China's crackdown on its flagship product iPhone.