Mumbai: The rupee on Monday opened at 66.15 vs a US dollar after soaring 85 paise to 65.70 against dollar on Friday. The BSE Sensex is over 100 points up at 18,721.72 while the Nifty is over 20 points up at 5,492.70.After plunging to record low of 68.85 on August 28, the rupee has rebounded, providing much-needed relief to the economy which grew at 4.4 per cent in the June quarter, the slowest pace in at least four years.