SAN ANTONIO — Brandon Roy scored 26 points and the Portland Trail Blazers took a big stride in the race for home-court advantage with a 95-83 victory over the San Antonio Spurs on Wednesday night.

Clawing back from an early 19-point deficit, Portland won in San Antonio for the first time since 2002 — and the timing was perfect.

Portland moved into a three-way tie with the Spurs and Houston for the third-best record (50-28) in the West with four games left. The Trail Blazers also took the season series 3-1, which could pay dividends if the seedings come down to tiebreakers.

Roger Mason scored 18 points for the Spurs, who lost for the first time since learning this week that Manu Ginobili will miss the postseason because of an ailing right ankle. San Antonio has lost four of six.

LaMarcus Aldridge scored 20 points for the Trail Blazers, who've won six of their last seven.

Tim Duncan, bothered by aching knees since the All-Star break, scored just four points in 24 minutes, playing in back-to-back games for the first time in six weeks — perhaps a sign of how much this one meant for the slumping Spurs.

The Spurs are in danger of letting home-court advantage in the first round slip away after holding the second-best record in the West for most of the season.

Tony Parker had 17 points and seven assists for San Antonio, which has another big West showdown Friday against Utah.

Portland won in San Antonio for the first time in 12 tries.

Notes: The Spurs are 18-16 without Ginobili in the lineup this season and 32-12 with him. ... The Spurs promoted G Marcus Williams from their D-League team in Austin and waived Malik Hairston before the game. Williams, a former Arizona standout, averaged a triple-double in three games last week for the Toros. ... Former Spurs great David Robinson watched his first game courtside since being elected to the Hall of Fame this week. The crowd treated him to an extended standing ovation.