Kasun Rajitha claimed his second five-wicket haul in Test cricket as Sri Lanka crushed Bangladesh by 328 runs on Monday in Sylhet to go 1-0 up in the two-match series.

The visitors bowled out Bangladesh for 182 in their second innings after lunch on the fourth day, with Rajitha returning with 5-56.

Overnight batsman Mominul Haque scored 87 not out for Bangladesh to delay the inevitable before Lahiru Kumara (2-39) took the final wicket.

Fast bowler Rajitha claimed the wicket of Taijul Islam in the third over of the morning, trapping the left-hander in front for six.

Mominul, who hit 12 fours and a six, put on a dogged 66-run partnership with Mehidy Hasan Miraz for the seventh wicket before Rajitha struck again.

Mehidy, on 33, edged Rajitha to Dhananjaya de Silva at second slip.

Rajitha took the wickets of Shoriful Islam (12) and Khaled Ahmed (zero) off consecutive deliveries after the break to complete his five-wicket haul.

Vishwa Fernando was the other pivotal bowler for Sri Lanka with 3-36 as pacemen took all 20 wickets for the visitors in the game.

"The wicket had something for the fast bowlers," said Sri Lanka captain and player of the match de Silva.

"We were talking about playing late, and what shots to play on this wicket. It paid off at the end of the day."

Taijul and Mominul resumed Bangladesh's innings at 47-5 after the top order collapsed in little over an hour before the close of play on Sunday.

"The wicket was good, there was movement early on," said Bangladesh captain Najmul Hossain Shanto.

"We have to improve our new-ball batting. A lot of work has to be done before the next Test, and we are going to have a plan to come back strongly."

Sri Lanka, who have never lost a Test series in Bangladesh, made 280 in their first innings and Bangladesh replied with 188.

The visitors then made 418 with first-innings century-makers de Silva and Kamindu Mendis both reaching three figures for the second time in the match.

They were only the third pair from the same country to score centuries in each innings of a Test after Australia's Chappell brothers, Greg and Ian, and Pakistan's Misbah-ul-Haq and Azhar Ali.

The second and final match of the series will be played in Chittagong from March 30.