Skipper Mahmudullah Riyad's unbeaten 83 was the only highlight on the second day of the first Test for the home side as it helped Bangladesh post 513 in the first innings, but since then it was Sri Lanka who capitalised on the docile pitch that was yet to offer much assistance to the spinners.

Mominul Haque, who resumed the day on an unbeaten 175, could only add one run before being caught off Sri Lanka left-arm spinner Rangana Herath in the third over of the day which started with Bangladesh on 374 for four.

The visitors then rode on Dhananjaya de Silva's brilliant form as he struck his third Test century and was unbeaten at the close with Kusal Mendis, who was also approaching his century as Sri Lanka ended the second day on a high after posting 187 for one at the Zahur Ahmed Chowdhury stadium in Chittagong yesterday.

Despite losing the first wicket of Dimuth Karunaratne without troubling the scorers when he edged off-spinner Mehedi Hasan Miraz at slip in the third over of the innings, the home side were unable to hold on to the momentum. Interestingly, Mehedi was immediately taken out of the attack as stand-in captain Mahmudullah -- captaining his first Test in place of the injured Shakib Al Hasan -- introduced left-arm spinners Taijul Islam and Sunzamul Islam from both ends for the two right-handers, a move that raised eyebrows.

After producing some turn and variable bounce initially at the beginning of the day, there was nothing much for the spinners or even for Mustafizur Rahman to test the two batsmen at the crease.

The unresponsive pitch aside, the home side did made a few mistakes that made things even easier for the Lankans.

In the early overs of the Sri Lanka innings, Mustafizur bent his back with the new ball in an effort to induce a mistake from the batsmen and a chance was offered when in the fifth over a struggling Mendis, on four, edged a delivery on off stump to at second slip where Mehedi went for the low chance to his left but was unable to hold on to it. Mendis was handed another life in the 31st over when, on 57, a well-disguised arm-ball from Mehedi caught the edge and flew towards the left of slip but Imrul Kayes was moving the other way and could not react in time to hold on to the catch.

De Silva at the other end looked rock solid, with some confidence in the bank with a Test century in his last innings against India in December 2017, and he remained the aggressor among the two batsmen and he struck Taijul for three fours just before tea, which Sri Lanka reached on 50 for one after 15 overs.

The Sri Lankan duo controlled the remainder of the day and soon De Silva struck a beautiful back-foot punch off Taijul to register his second consecutive hundred and remained unbeaten on 104 off 127 balls with 15 fours. Mendis was not out on a 152-ball 83.

The Bangladesh fielders and skipper Mahmudullah were overly optimistic in the last hour of the day and in the process wasted both their reviews.

It was a disappointing start to the day for Bangladesh when all eyes were on Mominul, but in just the third over of the day he was dismissed for the addition of only one run to his overnight score. The left-hander clipped Herath in the air and short-leg fielder Mendis managed to hold on after it hit his shoulder.

The veteran left-arm spinner came to the party and went on to pick two more Bangladesh wickets in the forms of Mosaddek Hossain and Taijul Islam. Mosaddek, back in the side for the first time since the two-Tests series against Sri Lanka in March 2016, was frustrated by Herath's accuracy and charged the bowler, but his attempted lofted drive only reached mid on and gifted Herath his 500th international wicket.

Mahmudullah, meanwhile, was the lone fighter and kept hopes of going past 500 alive. When on 69, he became the seventh Bangladesh batsman to score 2,000 Test runs. But the home side kept losing wickets.

Mehedi was run out for 20 going for a needless third run.  The Tigers skipper then added 58 for the eighth wicket with Sunzamul Islam, who was stumped down the leg side off Lakshan Sandakan for 24. Mahmudullah kept his trust on the tail-enders as Bangladesh had already gone past the 500 mark before Mustafizur, who struck a six off Herath, was eventually dismissed awkwardly fending a Suranga Lakmal bouncer to give the pacer his third wicket.