The left-arm spinner finished with 5-65, his 11th haul of five or more wickets in a Test innings, as Sri Lanka dismissed New Zealand for 221 in the first innings before reaching 9-1 in reply at stumps.
Nightwatchman Suraj Randiv was unbeaten on three while opener Tharanga Paranavitana had yet to open his account. Debutant opener Dimuth Karunaratne was trapped leg-before by fast bowler Tim Southee for no score.
Sri Lankan paceman Shaminda Eranga, playing only his second Test, was the other bowler to impress as he took two wickets off three overs in a lively opening spell to eventually finish with 3-51. New Zealand squandered the advantage of batting first on a good wicket at the Galle International Stadium after winning the toss as they faltered badly.