Sachdev, who knocked out former national champion Alok Kumar in the first round looked down and out after dropping the first three frames, but came back in fine fashion to make it 3-all with notable breaks of 54 and 45 in the fourth and fifth frames.
Sachdev, who came through four rounds of qualifiers, dropped the seventh frame to trail 3-4, won the eighth to draw level again but could not sustain the momentum and lost the deciding ninth frame to bow out of the tournament.
Divya Sharma of Haryana pulled off a 5-2 victory over former national 6-red champion Shahbaz Adil Khan of Bharat Petroleum by sweeping the last three frames after the two were tied 2-2.
In two other pre-quarter final clashes, Maharashtra's Shahbaz Khan defeated qualifier Manish Jain of Bengal 5-3 after staving off the latters determined fight-back, while Manan Chandra, the 2013 national champion, stopped qualifier Ishpreet Singh Chadha of Maharashtra 5-1.
Results (Pre-quarter-finals) Divya Sharma bt Shahbaz Adil Khan 5-2 (61-39,52-62,64-20,56-45,51-43,24-92(51), 59-1; Shahbaaz Khan bt Manish Jain 5-3: 106-10, 73-42,12-69,62-57,27-68,75-23,11-65,72-16; Manan Chandra bt Ishpreet Singh Chadha 5-1 (82-1,80-19,66-54,34-64,75-42,68-64); Sundeep Gulati bt Rahul Sachdev 5-4 (89(52)-31, 51-33, 66-10, 10-58(54),7-67(45), 59-64, 88-8, 12-72, 74-33).