The Sensex opened with a positive gap of 30 points at 11,175. The index slipped into red for brief while before bouncing back to touch a high of 11,213.Fresh round of selling coupled with terror threat in UK saw the index slip back into the negative zone. The index tumbled to a low of 11,052 - down 161 points from the day's high.However, the index recouped all its losses seeing strength in the European markets and ended on a flat note at 11,149, up four points.