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.
Sri Lanka turn to old warhorse Lasith Malinga to put fight into their Champions Trophy campaign and reverse their decline in the one-day game.
Former Sri Lanka captain Kumar Sangakkara will retire from first-class cricket in September at the end of England's county championship season.
Angelo Mathews will return as Sri Lanka skipper for the Champions Trophy after missing the ODI series against South Africa, the tour of Australia and the home series against Bangladesh.
A fit-again Angelo Mathews will lead Sri Lanka in June's Champions Trophy in England and Wales, the cricket board announced on Monday, unveiling a 15-member squad which also includes maverick paceman Lasith Malinga.
Opener Dhananjaya de Silva struck an unbeaten 78 to help Sri Lanka beat Zimbabwe by eight wickets on Monday in the opening match of the triangular one-day tournament that also features West Indies.
Australia will be looking to local legend and one-time bogeyman Muttiah Muralitharan to inspire them to success on his home patch as the world's number one Test team begin a three-match series in Sri Lanka this week.
Sri Lanka Cricket will refuse no-objection certificates to at least 16 centrally-contracted players seeking to take part in this year's Bangladesh Premier League, an SLC official says.