Colombo, Sri Lanka: India tightened its grip on the second Test against Sri Lanka despite a fighting century by Kusal Mendis during the hosts' follow-on in Colombo on Saturday.

Mendis put on 191 runs for the second wicket with opener Dimuth Karunaratne (92 not out) before falling to paceman Hardik Pandya for 110 just before stumps on day three.

The hosts were 209 for two at close, still trailing India by 230 runs in their second innings. Karunaratne and nightwatchman Malinda Pushpakumara on two were at the crease.

"Credit to them, they batted really really well. I don't think we did too much wrong," India's ace spinner Ravichandran Ashwin, who took five wickets in Sri Lanka's first innings, told reporters.

"Hopefully we will try and nick them off tomorrow. I think this wicket will get slower and slower. It is not going to be easy work tomorrow for sure," said Ashwin.

Earlier in the day, Sri Lanka nosedived from their overnight 50-2 to 183 all out at lunch, handing the visitors a chance to clinch the three-match series 2-0.

Wicketkeeper-batsman Niroshan Dickwella, who top-scored for the hosts with 51 in the first innings, said the team needs to back itself at the Sinhalese Sports Club Ground.

"We weren't good in the first session. We had plans before the second innings started," said Dickwella.

"Track is not difficult at all. We adapted brilliantly. We had a plan and we executed it well and that's the reason why we are 209 for two.

"We have to back ourselves 100 percent. We might get out playing positive shots... We are international players and we need to adapt quickly," Dickwella added. 

The islanders were in early trouble in the second innings when paceman Umesh Yadav got opener Upul Tharanga out for two after lunch on a seemingly deteriorating pitch.

- The marathon stand -

The left-right batting combination of Karunaratne and Mendis then dug in their heels to thwart the Indian bowling attack, forcing skipper Virat Kohli to rotate his options.

The duo handled the Indian spinners with aplomb, using their feet to good effect as they combined the right dose of caution and aggression.

"They both are great players. They executed the plans and used the crease and swept well. Mendis has been a brilliant player in his small career," said Dickwella.

Mendis, who hit his third Test hundred, played an attacking game as he smashed 17 boundaries before letting go of his hard work with a catch to wicketkeeper Wriddhiman Saha.

The Colombo-born Karunaratne remained patient during his 200-ball knock so far as he played out the remaining few overs with debutant Pushpakumara in a tense finish to the day.

But it was the first session that hit the hosts hard as they lost eight of their remaining wickets and conceded a 439-run lead in response to India's formidable 622-9 declared.

The Dinesh Chandimal-led Sri Lanka need at least a draw to stay alive in the series.