Ramesh Mendis led the Sri Lanka fightback at Galle with a six-wicket haul to bowl out the West Indies, but the hosts stumbled after returning to bat in the second Test on Wednesday.
Sri Lanka were 46-2 at stumps on day three, trailing by just three runs. But they lost Dimuth Karunaratne, who made six before he was run out in a superb piece of fielding by Kyle Mayers.
Karunaratne was man of the match in the first Test with scores of 147 and 83 but paid the price for attempting a quick early single as Mayers ran in and found him well short of the crease.
Oshada Fernando too was run out after being turned back by non-striker Pathum Nissanka.
With Angelo Mathews out with a hamstring injury, losing two early wickets was a massive blow for Sri Lanka. They have never lost a home Test to West Indies.
Earlier, off-spinner Mendis belatedly found his line and length, dismissing Nkrumah Bonner to end his 75-run stand with West Indies captain Kraigg Brathwaite.
It broke a two-session drought for Mendis, who then ran through the tourists' middle order, ending with figures of 6-70 as the West Indies were all out for 253 after tea -- a lead of 49.
The West Indies fell apart against the bounce of the new ball, though Mendis was denied a seventh wicket when wicketkeeper Dinesh Chandimal dropped Kemar Roach on eight.
Left-arm spinner Lasith Embuldeniya dismissed Brathwaite with a ball pitched on leg-stump that turned away sharply from the right-hander to clip the top of off-stump.
The West Indies, who have yet to win a Test match in Sri Lanka, were looking at a decent total and a considerable first-innings lead when they finished on 145-2 at lunch.
Brathwaite's straightforward footwork and impregnable defence were a vital bulwark for the West Indies after two top-order collapses in the first Test.
The skipper cashed in when loose balls were on offer and was relentless against Sri Lanka's two left-arm spinners, forcing the hosts to recalibrate to boundary protection.
But the afternoon collapse saw the visitors hand the initiative back to Sri Lanka on a fast-deteriorating wicket.
The second Test has been plagued by inclement weather and bad light, and Wednesday was the first full day played.
Sri Lanka lead the two-Test series 1-0.
Sri Lanka v West Indies 2nd Test scoreboard
Scoreboard at the end of day three of the second Test between Sri Lanka and the West Indies in Galle on Wednesday:
Sri Lanka first innings: 204 (Nissanka 73, Karunaratne 42; Permaul 5-35, Warrican 4-50)
West Indies first innings (overnight 69-1)
Kraigg Brathwaite b Embuldeniya 72
Jermaine Blackwood lbw b Jayawickrama 44
Nkrumah Bonner lbw b Mendis 35
Shai Hope lbw b Mendis 22
Roston Chase c Asalanka b Mendis 10
Kyle Mayers not out 36
Jason Holder lbw b Mendis 4
Joshua Da Silva b Mendis 0
Kemar Roach c de Silva b Jayawickrama 8
Veerasammy Permaul b Embuldeniya 15
Jomel Warrican c sub (Karunaratne) b Mendis 1
Extras: (nb 6) 6
Total: (all out, 104.2 overs) 253
Fall of wickets: 1-62 (Blackwood), 2-137 (Bonner), 3-166 (Brathwaite), 4-180 (Hope), 5-191 (Chase), 6-197 (Holder), 7-197 (da Silva), 8-208 (Roach), 9-246 (Permaul), 10-253 (Warrican).
Bowling: Suranga Lakmal 9-3-22-0 (nb 2), Lasith Embuldeniya 35-13-94-2 (nb 4), Ramesh Mendis 34.2-8-70-6, Praveen Jayawickrama 25-4-59-2, Dhananjaya de Silva 1-0-8-0.
Sri Lanka second innings
Dimuth Karunaratne run out (Mayers) 6
Pathum Nissanka not out 21
Oshada Fernando run out (Blackwood/da Silva) 14
Charith Asalanka not out 4
Extras: (lb 1) 1
Total: (two wickets, 21 overs) 46
Fall of wickets: 1-7 (Karunaratne), 2-39 (Fernando).
To bat: Dhananjaya de Silva, Dinesh Chandimal, Ramesh Mendis, Suranga Lakmal, Lasith Embuldeniya, Praveen Jayawickrama, Angelo Mathews.
Bowling: Veerasammy Permaul 9-2-20-0, Roston Chase 5-1-8-0, Jomel Warrican 7-1-17-0.