Spurs 118, Trail Blazers 103: Tony Parker led the way with 29 points and Tim Duncan added 19 as visiting San Antonio knocked off Portland to take a 3-0 lead in the Western Conference semifinals.Kawhi Leonard collected 16 points and 10 rebounds for the Spurs, who can close out the series in Game 4 at Portland on Monday. Manu Ginobili contributed 14 points off the bench as San Antonio replicated its formula from the first two games with a blistering first half and an easy second.LaMarcus Aldridge recorded 21 points and 12 rebounds and Wesley Matthews scored 22 for the Trail Blazers. Damian Lillard had 21 points and nine assists while Nicolas Batum scored 20 for Portland, which allowed the Spurs to shoot better than 55 percent in the opening half for the third straight game.San Antonio used a 10-0 run to open up a 103-81 lead with 7:43 left before the Trail Blazers made their final push, ripping off the next 10 points to cut it to 12 before Parker and Leonard hit two free throws apiece to stretch it back out. Leonard's 3-pointer with 2:49 to play made it a 114-97 cushion as the Spurs put it away.San Antonio led 28-18 at the end of the first quarter and maintained a double-digit advantage through the second that ballooned to as much as 58-35 on Parker's late 3-pointer before the Spurs settled for a 60-40 lead at the break. Portland put together its best stretch early in the third and drew within 64-57 with 7:24 remaining in the period before the Spurs recovered to take a 14-point lead into the fourth.GAME NOTEBOOK: Portland has only led for 33 seconds in the entire series. … The Spurs went 25-of-25 from the free-throw line, led by Ginobili's 10-of-10. … Lillard went 0-of-6 from 3-point range and is just 1-of-13 from beyond the arc in the series.