Sensex closed at 85,641.90, down 64.77 or 0.08 per cent. The 30-share index opened with a decent gap-up at 86,065.92 against the last session's closing of 85,706.67. The index, however, did not hold the gaining momentum amid a cautious approach from investors. Nifty settled at 26,175.75, down 27.20 points or 0.10 per cent.