Caught in the Monday blues, both the Sensex and Nifty gave a gap-down opening on February 24, slipping into the red for the fifth consecutive session. The BSE Sensex crashed 856.65 points, or 1.14 per cent, to close at 74,454.41, while the Nifty 50 declined by 242.55 points, or 1.06 per cent, to end the session at 22,553.35.