Bangladesh team, which was placed in four-team Pool B of the Asian Games Qualifier with Indonesia, Sri Lanka and Singapore, will play lowly Singapore on 12 May in their last group match.
In the day's match, Ashraful Islam put Bangladesh ahead in the third minute of the second quarter by a penalty corner after goalless in first quarter (1-0).
Bangladesh sounded their margin in the eighth minute of the same quarter from a penalty stroke (2-0).
Sri Lanka pulled the margin one back in the last minute of the 3rd quarter after spoiling five consecutive penalty corners (2-1).
Roman Sarkar sealed the fate of the match scoring the 3rd goal for Bangladesh in the 8th minute of the 4th and final quarter (3-1).
Sri Lanka managed a penalty corner just 28 seconds before the match over but failed to score.
Earlier on Saturday, Bangladesh team made a good start in the nine-nation Asian Games qualifier beating Indonesia by 3-1 goal with medio Sarwar Hossain, forward Pushkar Khisha Mimo and midfielder Fazle Hossain Rabbi scoring one field goal each for Bangladesh.
Sri Lanka also made a flying start in the Asian Games qualifier outplaying Singapore by 5-2 goal in their first match last Saturday.
On completion of the Asian Games qualifier, the Bangladesh team, led by new captain Khorshedur Rahman, will travel to Indonesia directly from Thailand to compete in the Men's Asia Cup Hockey to be held in Jakarta from 23 May to 1 June.
In the eight- nation Hero Men's Asia Cup Hockey, Bangladesh team also has been placed in Pool B with Malaysia, Korea and Oman.
Bangladesh will face Korea on 23 May, Oman on 24 May and Malaysia on 26 May.
Earlier, Bangladesh qualified for the Hero Men’s Asia Cup Hockey by clinching the Men's AHF Cup Hockey title for the fourth consecutive times in Jakarta last March.