Chaminda Vaas lost his nerves, but Shivnarine Chanderpaul kept his, and struck a four and a six off the last two balls to hand West Indies a sensational one-wicket victory over Sri Lanka in the first One-Day International here Thursday. Chasing 236 for victory from its allocation of 50 overs, West Indies entered the final over at Queen's Park Oval needing 13 runs to win. Sri Lanka turned to Vaas, its most experienced bowler and he restricted the West Indies last wicket pair of Chanderpaul and batting bunny Fidel Edwards to three runs from the first four balls of the over. But Vaas, whose line and length had been unerring throughout the match, delivered a full length delivery and Chanderpaul drove him through mid-off for four. Sri Lanka would still have favored its chances with West Indies needing a six off the last ball when Vaas delivered a full toss which Chanderpaul duly dispatched over the wide long-on boundary to spark massive celebrations in the stands. Chanderpaul was undefeated on 62 from 63 balls. The victory gives West Indies a 1-0 lead in the three-Test series which continues at the same venue on Saturday before ending next Tuesday with a day/night fixture in St. Lucia. A record sixth-wicket stand of 159 between Chamara Silva and Chamara Kapugedera had helped Sri Lanka reach a respectable 235 for seven off its allotment of 50 overs, after it was sent in to bat on a hard, true pitch under partly cloudy skies. Kapugedera struck seven fours and three sixes in the top score of 95 from 117 balls and Silva collected seven boundaries in 67 from 96 balls to get Sri Lanka back on course, after Dwayne Bravo triggered a slump that restricted them to 49 for five in the 15th over. Then openers Chris Gayle and Devon Smith emerged from an uneasy start to give West Indies a solid foundation of 53 for the first wicket. Kulasekera made the breakthrough, when he gained a dubious lbw verdict to dismiss Smith for 14. Sri Lanka was made to toil for almost 13 overs before it scalped another wicket, as Ramnaresh Sarwan joined Gayle and they added 56 for the second wicket. But Sri Lanka savored a purple patch, when it captured three wickets in the space of seven balls to leave West Indies 110 for four in the 28th over. Scoreboard Sri Lanka Tharanga b Bravo 10 Udawatte b Edwards 00 Sangakkara c Bravo b Taylor 23 Jayawardene c Chanderpaul b Bravo 01 Silva c Gayle b Bravo 67 Dilshan c Browne b Bravo 02 Kapugedera lbw b Edwards 95 Vaas not out 10 Kulasekera not out 01 Extras (lb16, w10) 26 Total (for 7, 50 overs) 235 Did not bat: A. Mendis, I. Amerasinghe Falls: 1-2 (Udawatte, 1.3 overs); 2-38 (Sangakkara, 9.1); 3-40 (Tharanga, 10.4); 4-41 (Jayawardene, 12.3); 5-49 (Dilshan, 14.5); 6-208 (Silva, 46.2); 7-234 (Kapugedera, 49.5). Bowling: Taylor 10-1-39-1; Edwards 10-0-57-2 (w8); Bravo 10-1-33-4 (w1); Sammy 10-1-38-0 (w1); Benn 9-0-46-0; Gayle 1-0-6-0. West Indies Gayle lbw b Mendis 52 Smith lbw b Kulasekera 14 Sarwan c Sangakkara b Kulasekera 35 Samuels lbw b Kulasekera 00 Chanderpaul not out 62 Bravo run out (Jayawardene) 36 Browne c Mendis b Dilshan 15 Sammy b Mendis 01 Taylor c Silva b Mendis 09 Edwards not out 02 Extras (lb1, w9) 10 Total (for 9, 50 overs) 236 Falls: 1-53 (Smith, 13.3 overs); 2-109 (*Gayle, 26.6); 3-109 (Sarwan, 27.3); 4-110 (Samuels, 27.6); 5-169 (Bravo, 38.1); 6-201 (Browne, 44.4); 7-203 (Sammy, 45.4); 8-219 (Taylor, 47.6); 9-219 (Benn, 48.5). Bowling: Vaas 10-4-30-0; Kulasekera 10-0-43-3; Amerasinghe 7-0-56-0; Mendis 10-1-39-3; Kapugedera 7-0-41-0; Dilshan 6-0-26