This series win crowns a strong three months for Sri Lanka under new head coach Sanath Jayasuriya.
Sanath Jayasuriya was appointed Sri Lanka cricket head coach on Monday, replacing Chris Silverwood who quit following the country's early exit from the T20 World Cup.
Shanaka, who led Sri Lanka to victory in the 2022 T20 Asia Cup, was replaced as captain by Wanindu Hasaranga in December following the team's poor showing in the last three white-ball World Cups.
Sri Lanka were in dire straits at 6-3 after skipper De Silva won the toss, losing their first three wickets for no runs in 10 balls.
Dilshan Madushanka has been named as Thushara's replacement in the squad while Asitha Fernando has been named as Chameera's replacement.
The 26-year-old all-rounder quit following Sri Lanka's early exit from the T20 World Cup in June.
Sri Lanka's sports ministry has dispatched an officer to the United States to look into the welfare of the team, Fernando added.
Bangladesh enter the T20 World Cup with a bit of uncertainty as they continue to look for their strongest XI. Experienced opener Litton Das has been out of form of late with an average of 13.16 this year in six matches. Although teammate Tawhid Hridoy is confident that Das will make a strong comeback in the tournament.
Of the nine teams that have managed to play all the editions of the T20 World Cup since its inauguration in 2007 (Bangladesh, West Indies, India, Australia, England, Pakistan, Sri Lanka, New Zealand, and South Africa), the Tigers are the only side to have never qualified for the semifinal of the tournament.
Australian former international Tom Moody is set to leave his post as Sri Lanka's director of cricket, officials said on Monday, weeks before the T20 World Cup.
Dasun Shanaka's Sri Lanka beat Pakistan by 23 runs in Dubai on Sunday to clinch their sixth Asia Cup.
Bhanuka Rajapaksa on Sunday said Sri Lanka's cricket has proved a point to the world with their sixth Asia Cup title after his unbeaten 71 set up a commanding 23-run win over Pakistan.
Batsman Bhanuka Rajapaksa said Sri Lanka have shaken off their underdogs tag and proved they can challenge at next month's T20 World Cup, after beating India to stand on the verge of the Asia Cup final.
Powerful innings by Kusal Mendis and skipper Dasun Shanaka helped Sri Lanka pull off a thrilling two-wicket win over Bangladesh to make the Asia Cup Super Four stage on Thursday.
Sri Lanka's resounding 246-run victory over Pakistan in the second Test in Galle has seen them break into the top five of the ICC World Test Championship standings.
Dhananjaya de Silva hit a towering century as hosts Sri Lanka handed Pakistan a mammoth victory target of 508 in the second Test on Wednesday
Sri Lanka captain Dimuth Karunaratne batted through pain to help the hosts stretch their overall lead to 323 runs and boost their chances of a series-levelling victory in the second Test against Pakistan on Tuesday.
Ramesh Mendis chipped in with a lower order cameo and then claimed three wickets for 42 runs to put Sri Lanka on course for a significant first innings lead against Pakistan on day two of the second test in Galle on Monday.
Cricket-obsessed Percy Abeysekera has been a constant presence at Sri Lanka matches since their first Test against England in 1982 -- and even the country's worst economic crisis cannot keep him away.
