They signed off at 16th and 19th respectively on the second and final day of qualification.
While Manavjit had scores of 23, 23, 22, 25, 22 for a total of 115, Chenai ended up with 22, 23, 22 24, 23 for a total of 114.
Only the top six from the two-day qualifiers made the cut for the semi-finals.
It was particularly disappointing for Manavjit, who had pulled himself into contention by being placed 8th at one stage with a perfect 25 in the fourth round.
However, he could not sustain the form and ended with a 22 in the final round to finish at a disappointing 16th.
Chenai, on the other hand, could never rise from Sunday’s 19th.
Italy’s Giovanni Pellielo topped the two-day qualifications with a score of 122, followed by Brit Edward Ling (120).
Croat Josip Glasnovic (120) was third.
IMAGE: Manavjit Singh Sandhu in action during his routine in the men's Trap semi-finals at the Rio Olympics.
Photograph: Edgard Garrido/Reuters
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