New Delhi, Sep 8 : Nifty registered the best week in two months after rising for six consecutive sessions on Friday, Deepak Jasani, Head of Retail Research, HDFC Securities, said.  Volumes on the NSE again spiked to higher than recent average. Midcap index rose more than the Nifty even as the advance decline ratio stayed high at 1.15:1, he said. Global stock markets dipped on Friday, with tech shares tumbling on deepening Sino-US tensions and slowing global growth and uncertainty over the path of US monetary policy impacting the other sections of the markets. The offshore Chinese yuan weakened to its lowest level against the US dollar since its inception in 2010, crossing the 7.35 level early this morning to trade at 7.3599 yuan per dollar. The Reserve Bank of India has decided to roll back incremental cash reserve ratio, or I-CRR, in a phased manner following a review on Friday. RBI is expected to release 25 per cent of the I-CRR maintained on September 9. Further, 25 per cent of the I-CRR to be released on September 23. Last 50 per cent of I-CRR maintained to be released on October 7, he said. Rupak De, Senior Technical analyst at LKP Securities said the Nifty displayed strength, primarily driven by strong demand for large-cap stocks. The overall trend remained robust as the index consistently stayed above a critical moving average. However, a significant hurdle for the Nifty came in the form of substantial Call writing at the 19,900 strike price. /IANS