If the Nifty 50 decisively breaks the 23,800 support level (the 50 percent Fibonacci retracement of the recent rally), the start of a corrective phase cannot be ruled out. In that case, the 23,600-23,500 zone will be the key area to watch. On the upside, 24,000 is likely to act as the immediate hurdle, followed by 24,200, according to experts.