Opener Saif Hassan and Towhid Hridoy struck spirited fifties to back their frugal bowlers as Bangladesh registered a nervy four-wicket win over Sri Lanka in their Asia Cup Super Fours match here on Saturday.Sri Lanka made 168 for seven, riding on Dasun Shanaka’s powerful 64 (37 balls), but Bangladesh found perfect riposte in Saif (61, 45 balls) and Hridoy (58, 37 balls), ending up at 169/6 in 19.5 overs.Bangladesh never really floundered in a tricky chase despite losing Tanzid Hasan in the first over itself to Nuwan Thushara.Skipper Litton Das gave good company to Saif as the pair added 59 runs for the second wicket in 5.2 overs.Saif was in flowing touch as he carted left-arm spinner Dunith Wellalage, who joined the team after visiting home to attend his father’s funeral, for two sixes before adding another maximum off Thushara.Saif reached his fifty in 35 balls but lost Das to Wanindu Hasaranga.Saif then had a nice little alliance of 54 for the third wicket with Hridoy, who punished spinner Kamind Mendis for 16 runs in the 15th over, as Bangladesh moved closer to the target.Story continues below this adBut the right-hander perished to Hasaranga in his attempt to find further acceleration, leaving Hridoy to complete the chase, a task he almost completed before falling to Dushmantha Chameera.The wicket saw Bangladesh panicking a bit in the last over, losing two wickets but they managed to move across the line.Earlier, Bangladesh bowlers were largely consistent with their line and length, but Shanaka’s powerful fifty carried Lanka to a competitive 168 for seven.Sent in to bat first, Lanka made a swift start to the innings as Pathum Nissanka (22, 15 balls) and Kusal Mendis (34, 25 balls) added 44 runs in 5 overs.Story continues below this adNissanka biffed pacer Shoriful Islam for three fours in a row, while Mendis smashed left-arm spinner Nasum Ahmed for a six as Lanka found early momentum.But the dismissal of Nissanka, an uppish flick off pacer Taskin Ahmed found Saif Hassan in the deep, changed the course of the match, till Shanaka revived Sri Lanka with a top knock.Mendis departed soon, skying left-arm spinner Mahedi Hasan to Saif Hassan near backward square leg as Lanka slipped to 58 for two.Kamil Mishara and Kusal Perera never really got going as the boundaries dried up in the middle overs.Story continues below this adDuring that phase, Lanka could not find the boundary ropes for nearly five overs, but they might have considered the dismissals of both Mishara and Perera as a blessing.Spinner Mahedi and pacer Mustafizur Rahman (3/20), the most successful Bangladesh bowler, kept the SL batters in manacles with pace-off deliveries and cutters.Mishara went for a reverse lap against Mahedy to get castled and Perera edged Rahman to stumper Liton Das as SL found themselves at 97 for 4 in 13.4 overs.But former skipper Shanaka and his successor Charith Asalanka (21) shared a 57-run alliance for the fifth wicket stand to bail out Sri Lanka.Story continues below this adLeft-arm spinner Nasum was the one who really felt the power of Shanaka as the Lankan hammered him for 4, 6, 6, the last one a thundering sweep, to push his side forward.However, the run out of Asalanka ended that alliance and brought Bangladesh back into the match before Shanaka squeezed a four and six off Taskin in the last over.