Backed by bouyancy in global markets, the Sensex opened with a positive gap of 129 points at 17,902, and soon rallied to a fresh all-time intra-day high of 17,983 - just 17-odd points shy of the 18,000-mark. Once again, resistance at higher levels saw the index pare gains and slip into the negative zone. Aggressive profit-taking saw the Sensex tumble to a low of 17,322 - down 661 points from the peak. Selective buying, thereafter, helped the index recover partially towards the close.The Sensex finally ended (provisional) with a loss of 324 points at 17,449.