SAN ANTONIO (AP) Kawhi Leonard and the San Antonio Spurs turned a tense game into a lopsided laugher.

Leonard had 20 points and the Spurs beat Memphis 106-74 on Sunday night in Game 1 of the Western Conference first-round series, handing the Grizzlies their worst postseason loss.

San Antonio had 13 steals and nine blocks, with Leonard finishing with four steals and three blocks.

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''He's just aggressive,'' said Vince Carter, who led Memphis with 16 points. ''He's in passing lanes, he has great on-ball instincts, great hands and he blocks shots very well at his position as well. So, even if he gets beat, he can recover. He has very long arms. He's just relentless, and he really gets their defense started.''

Leonard was aggressive from tipoff, stripping Matt Barnes on Memphis' opening possession and turning the steal into a breakaway dunk.

''I got some easy shots going into that transition, getting some layups and dunks,'' Leonard said. ''That's how you get in rhythm, for my teammates as well. If they're able to get an easy layup, they're just going to gain more confidence.''

LaMarcus Aldridge added 17 points, and Tony Parker had 15 points and six assists for San Antonio. The Spurs sat their starters in the fourth quarter to rest them for Game 2 on Tuesday night in San Antonio.

San Antonio shot 68 percent in the third quarter, outscoring Memphis 33-14 to break open what had been a relatively close game against the short-handed Grizzlies.

''When you're playing against a team like this at home, you have to value the basketball and you have to hit shots as well,'' Carter said. ''When we're turning the ball over and not hitting shots, the lead can go from a five-point game to a 15- to 20-point game in the blink of an eye. That's what happened for us and I think that rattled us a little bit.''

Memphis matched a postseason low in the first quarter with 13 points, and only Xavier Munford's 15-foot jumper with 46.1 seconds remaining kept it from matching the worst output in any quarter.

Zach Randolph was held to six points on 3-for-13 shooting.

The Spurs ran a series of defenders and double teams to harass Randolph, the only remaining player among the team's top three scorers. Randolph had a shot blocked by Leonard in the first quarter, had Leonard step in front of him for a steal, and Tim Duncan ripped an inlet pass from his arms in the third quarter.

''Kawhi's a very good defender, and he takes great pride in it,'' San Antonio coach Gregg Popovich said. ''He did what he usually does for us. It's important. He sets the tone for us defensively, and tonight was a good example of that.''

Memphis' largest previous postseason losing margin was 27 points against Oklahoma City on May 11, 2011.

''It don't matter if we would have won by one, lost by 30 or won by 15, we're just trying to get one game,'' Randolph said.

Memphis was able to keep the game close in the first half despite being without starters Marc Gasol and Mike Conley, but San Antonio closed the second quarter on a 9-0 run leading into its dominant third.

''It just takes a little while to get going,'' Duncan said. ''Whatever you want to call it. Playoff jitters. It just took us a quarter or two to get our rhythm going. We got it going defensively. We were solid the whole way through and then some shots started falling. We kind of extended that lead. I think just giving ourselves a quarter or two to get ourselves rolling.''

CAUTIONARY TALE

The lopsided victory enabled Popovich to rest his core players and also be cautious.

Aldridge's right pinkie finger is still sore and bandaged after dislocating it April 7 at Golden State. Boris Diaw was playing in his second game after missing five straight with a sore right abductor.

''A couple of guys got a little banged up,'' Popovich said. ''LaMarcus on his hand, and Boris' groin, so it was a little bit more than rest. But they're pros and they've all been in the league a long time.''

MORE HISTORY

Duncan played in his 242nd postseason game, the third-most in league history. He trails former teammate Robert Horry by two games and former Lakers guard Derek Fisher by 17.

TIP-INS

Grizzlies: The Grizzlies' postseason low in any quarter was 11 in the fourth quarter against the Spurs on April 19, 2004. ... Memphis used an NBA-record 28 players this season. ... Grizzlies coach David Joerger was assessed a technical foul with 7:51 remaining after arguing a non-call on a turnover that led to Leonard's fast-break dunk.

Spurs: San Antonio's largest margin of victory in the postseason is 40 points against Denver on May 4, 1983. ... The Spurs outscored Memphis 406-356 during the regular season, winning by an average of 12.5 points. ... San Antonio is in the postseason for the 19th consecutive season, the league's longest active streak. Atlanta is second with nine consecutive appearances. ... San Antonio trailed for only 25 seconds following a 3-pointer by Carter 1:42 into the game.