Sri Lanka 222 (Mendis 68, Roshen 56, Razzak 4-63, Taijul 4-83) and 226 (Roshen 70*, Taijul 4-76) beat Bangladesh 110 (Dananjaya 3-20, Lakmal 3-25) and 123 (Dananjaya 5-24, Herath 4-49) by 215 runs
Dhaka: Bangladesh plunged, Sri Lanka's spinners soared and the Mirpur Test tore to its conclusion midway through day three, the visitors triumphing by 215 runs in Dhaka on Saturday.
Debutant Akila Dananjaya was prime destroyer. He scythed rapidly through the Bangladesh lower middle order, taking 5 for 24 to make it eight wickets on debut - the best performance by a Sri Lankan on debut.
The charge to victory was also sweet for Rangana Herath, who claimed 4 for 49 and in doing so, became the most successful left-arm bowler in Test history.
Perera removed opener Tamim Iqbal for two before Herath got rid of Imrul Kayes as Bangladesh reached 57-2 at lunch on the third day at the Sher-e-Bangla National Stadium.
Wicketkeeper Niroshan Dickwella took the catch as Kayes fell for 17 in the next ball after he hit Herath for six straight over his head.
Only four batsmen made it into double figures, and no one batted for longer than 51 deliveries.
Earlier, Sri Lanka added 26 runs to their overnight score before they were all out for 226 in their second innings to set up a mammoth target for Bangladesh.
Roshen Silva remained unbeaten on 70, adding 48 runs to fellow overnight batsman Suranga Lakmal for the ninth wicket after Sri Lanka resumed on 200-8.
Left-arm spinner Taijul Islam bowled Lakmal for 21 to end the partnership before he trapped Herath leg-before off the next ball to wrap up the Sri Lanka innings.
Taijul finished with 4-76 taking his tally to eight wickets in the match.