The San Antonio Spurs have locked up another No. 1 seed.

Now comes trying not to blow it again.

Tim Duncan scored 18 points in what might have been his last game before the playoffs start this weekend, now that the Spurs have clinched the top spot in the Western Conference after beating the Portland Trail Blazers 124-89 on Monday night.

The Spurs won their eighth in a row but won't care about the streak or little else with two now-meaningless regular season games left. All that will matter is their Big Three reaching the postseason fully healthy for the first time since 2008, and that likely means an easy week ahead for Duncan, Tony Parker and Manu Ginobili.

"It's great to be in that situation, but as we showed last year, someone can sneak up and take you out easily," Duncan said. "Hopefully we get a much better effort this year and do a much better job this year, and we stay away from those injuries."

After cruising to the No. 1 spot last season against all expectations, the Spurs bowed out as just the fourth top seed to lose in the first round. This latest one — their sixth top seed in the Duncan era — is somehow even more surprising. Two days before Duncan turns 36, the NBA's standard-bearers beat out the young Oklahoma City Thunder for ultimate home-court advantage.

Wesley Matthews had 24 points for the Trail Blazers, who lost their sixth straight and have one game left in a tumultuous season in which the franchise effectively hit the reset button.

J.J. Hickson had 14 points and 10 rebounds for Portland. Raymond Felton scored 13 points and Jonny Flynn had 10 on a night when the injury-depleted Trail Blazers again only used nine players.

"If we knew we were going into the playoffs, of course we're going to keep playing," Matthews said. "But now, shorthanded, nine players — I'm never going to say I'm looking forward to not playing basketball. But the season's winding down for us and we got one more left."

San Antonio could also know its first-round opponent as early as Tuesday. That's when Phoenix plays at Utah in a game that could decide the No. 8 seed.

Danny Green also had 18 points for the Spurs, while Parker scored 13 and Stephen Jackson and Gary Neal both added 12.

Neal left in the fourth quarter clutching his shoulder after colliding with Portland's Kurt Thomas. Popovich said X-rays were negative and called it a stinger.

Duncan wouldn't predict how Popovich would set his lineup the rest of the week to prevent any other scares.

"Obviously, we don't want to do to go into a game somebody get hurt from some silly play," Duncan said.

Portland is skidding toward a merciful end of its first season out of the playoffs in four years. Their losing streak is at a season high and interim coach Kaleb Canales — who grew up two hours south in the border city of Laredo — was humiliated in his homecoming.

"It was a great challenge for us coming in, playing a team that had a lot to play for tonight. We're getting thrown into the fire and we just didn't respond on the defensive end of the floor," Canales said.

It was the Trail Blazers' most lopsided defeat since Canales took over in March after Nate McMillan was fired. Before the game Canales, the NBA's first Mexican-American coach, played down the emotion of being home with a caravan of friends and family watching in the stands.

Not to mention working down the bench from the coach who taught him basketball basics as a kid.

Canales is 33. Popovich, when he was an assistant under then-Spurs coach Larry Brown in the late 1980s, would join other Spurs coaches and players on promotional bus tours along the Texas border to drum up interest. Popovich still recalls one of the youngsters at a stop outside a Laredo grocery store.

"I taught him all he knows as far as dribbling skills are concerned in the parking lot at the H-E-B," Popovich said.

Notes: The 35-point win tied for San Antonio's biggest blowout this season. ...Canales said he cold-called Spurs general manager R.C. Buford while trying to get his break in the NBA. Buford had nothing for him, but Canales said he was nice enough to call back.