That was to be Bangladesh's last taste of success for the remainder of the day as Dhananjaya and Mendis amassed an unbeaten 187-run partnership, during which Dhananjaya brought up his hundred and Mendis surpassed his fifty, before stumps was called.
Mendis (83 not out) and De Silva (104no) came together after opener Dimuth Karunaratne fell for a nine-ball duck, caught off Mehidy Hasan.
Mehidy was the only bowler to take a wicket. It could only take a counter-attack to get a move on with proceedings for Sri Lanka.
Trailing by 513 runs, Sri Lanka got off to a frightful start as they had yet open the scoring when opener Dimuth Karunaratne was caught by Imrul Kayes at first slip off the bowling of Mehidy.
Dhananjaya de Silva crafted a superb century and Kusal Mendis returned to form as Sri Lanka hit back on day two of the first Test against Bangladesh in Chittagong. On a slow pitch, Herath extracted grip and turn and made batting tough for the Bangladesh batsmen early on. The 26-year-old posted his fifth Test century and the first in more than three years off just 96 balls, with back-to-back fours off left-arm wrist spinner Lakshan Sandakan.
Mosaddek struggled during his stay in the middle, especially against Herath, and trying to play one against the spin, he mishit it straight to mid on. Since that juncture, however, overnight batsman Mahmudullah collaborated with the lower order to help Bangladesh finish with a 500-plus total.
Suranga Lakmal struck with the second new ball to claim two wickets off successive deliveries and gave Sri Lanka some respite late into the final session.
- BT Openreach sets higher target for 3m fibre broadband connections
- Egypt's Elneny praises Aubameyang's arrival, announces Ozil stay
- PyeongChang Winter Olympics to be coldest since 1994 Lillehammer
- North Korea strikes back at 'racist' Trump govt
- EnLink Midstream Partners (NYSE:ENLK) Research Coverage Started at Credit Suisse Group
- Union Finance Minister Arun Jaitley announces world's largest health insurance programme
- Google's Calculator app hits 100 million downloads on the Play Store
- Confirmed: Tottenham Hotspur v Manchester United lineups at Wembley
- James Corden hits back at Nikki Haley over Grammys
- Officials confirm Maiduguri attack, say 5 killed, 39 injured