Asalanka's 97* and middle order boost led Sri Lanka to a solid 308/6 victory foundation.
Afghanistan collapsed after a promising start, losing 8 wickets for 25 runs, ending at 153.
Zadran and Shah's 97-run stand shined before their exit led to Afghanistan's quick collapse.
Hasaranga's 4 for 27 crucially dismantled Afghanistan, reinforcing his key player status for Sri Lanka.
Hasaranga, Fernando, and Madushanka led Sri Lanka's bowling attack, flawlessly executing plans against Afghanistan.
Sri Lanka rebuilt and accelerated after losses, with Asalanka-Hasaranga's partnership key to formidable total.
Afghanistan's fielding errors and dropped catches allowed Sri Lanka to capitalize, extending their total past 300.