bounded in, making the early incisions, allrounder Milinda Siriwardana struck either side of lunch, and offspinner Dilruwan Perera took care of the tail, as West Indies were bowled out for 163, giving Sri Lanka a 37-run lead by tea on the second day, at the P Sara Oval. The lead was built further by Kusal Mendis and Kaushal Silva, who added 54 together, the highest partnership of the Test so far.
Mendis may have looked jittery in the first innings but he got going in the second dig with some wristy flicks. He began with three fours and sussed out the conditions better after Dimuth Karunaratne was dismissed first ball when he tamely chipped Jerome Taylor to square leg.
The other opener - Kaushal Silva - also had jitters. He was given out lbw on 3 before a review rescued him, with the tracker confirming that the ball was sliding down leg.
Mendis' promising innings was cut short at 39 by Jomel Warrican, but Dinesh Chandimal, having survived a tighter lbw review on 4, and Silva saw their team through to stumps while pushing the lead past 100.
Kraigg Braithwaite had earlier mounted some fight for West Indies with 47 off 101 balls, and it was extended through a 32-run seventh-wicket partnership between Denesh Ramdin and Jason Holder. Rangana Herath continued to be a wicket-taking threat, but had success only in his 17th over when Ramdin missed an agricultural swipe. Not that Sri Lanka complained.
Prasad, who led the attack, explored shorter lengths to begin with, but soon settled into his groove and returned figures of 5-2-8-2 in an energetic first spell. Nuwan Pradeep exploited the uneven bounce well enough to complement Prasad. Devendra Bishoo, the nightwatchman, was the first to fall on the second day when he threw his bat outside off, nicking Prasad behind, for 14.
Prasad then welcomed Darren Bravo with one that misbehaved, snaking away wide outside off and beat the outside edge with a full tempter. Prasad got the big eyes and the big smile going. What followed was a sequence of 19 dots with Sri Lanka burrowing into the middle order. A few balls spat from a length while others kept low, asking more questions of the batsmen.
The pressure on Bravo eventually told, with the batsman offering an indecisive angled bat and chopping Prasad on for 2. Herath added to West Indies' worries by employing teasing flight and ripped one viciously past the outside edge of Brathwaite. Prasad then got to bowl to Brathwaite for the first time on the second morning, 45 minutes after a delayed start due to a damp outfield caused by overnight rain, and had the opener scoop the first ball just wide of short cover.
Brathwaite had endured more dicey moments, but his innings ended when he was given out caught behind by umpire Rod Tucker. The noise may have come from the bat jamming the ground but there was not enough evidence to overturn the on-field decision. Marlon Samuel's innings was far more painstaking - he survived two leg-before appeals on zero within his first five balls, and was left scoreless for another ten balls. He weathered two more leg-before appeals and was caught at slip, lazily pushing at a tossed-up ball from Siriwardana to leave his side at 76 for 4, eight balls before lunch.
If it was any consolation, though, Samuels avoided his ninth single-digit score against Sri Lanka in 16 innings, nudging his average to double-figures.
Jermaine Blackwood flickered briefly - he drilled Pradeep through mid-off after a slow start and launched Siriwardana for a straight six - before Prasad returned and struck with the first ball after lunch. Holder also showed intent when he jumped out of the crease and sent Dilruwan clattering towards the media box.
However, Ramdin and Holder exited in a space of 19 balls and the tail did not wag, as the hosts gained what appeared to be a substantial lead on a pitch that already had puffs of dust exploding from the surface. This was only the first time since 2006 that Sri Lanka had managed a first-innings lead after making 200 or fewer when batting first.
Deivarayan Muthu is a sub-editor at ESPNcricinfo