Sri Lanka lead the West Indies by 279 runs, having reached 328-8 at stumps on day four of the second test in Galle on Thursday.
Sri Lanka who began the day on 46-2, were led by Dhananjaya de Silva with 153 not out, while Pathum Nissanka also chipped in with 66. Veerasammy Permaul took 3-94, while Roston Chase had 2-73.
West Indies head coach Phil Simmons believes it will be an uphill task for the Caribbean side on day five.
Sri Lanka lead the two match test series 1-0. Scores in the match: Sri Lanka - 204 and 328-8; West Indies - 253.