Jusuf Nurkic added 12 points for the Blazers, who have opened the season with a pair of home wins. They led the Spurs by as many as 20 points in the fourth quarter after a close first half.
DeMar DeRozan had 28 points and nine rebounds in a second strong performance after coming to the Spurs in an offseason trade.
DeRozan had 28 points in his San Antonio debut Wednesday in a 112-108 victory over the Minnesota Timberwolves.
He was traded from Toronto in July along with Jakob Poeltl in exchange for Kawhi Leonard and Danny Green. DeRozan wasn't happy about the deal, especially in light of his close friendship with Toronto teammate Kyle Lowry, but he appears to have developed a nice chemistry with his new team.
His arrival also signaled the end of the Big Three era in San Antonio. Tony Parker left the Spurs to sign with Charlotte in the offseason and Manu Ginobili joined Tim Duncan in retirement.
The Blazers opened the season with a 128-119 victory over the Lakers, spoiling LeBron James' debut with the team. Lillard had 28 points and Nik Stauskas came off the bench to score 24 for Portland, which won its 18th straight home opener to extend an NBA record.
Portland's season has started on a somber note following the death of owner Paul Allen. The enigmatic co-founder of Microsoft died Monday in Seattle from complications of non-Hodgkin's lymphoma. He was 65.
Lillard's first basket was a 3-pointer from well beyond the arc.
Portland extended its lead to 47-38 on Al-Farouq Aminu's 3-pointer. The Blazers led 59-50 at the break, led by Lillard with 14 points. DeRozan had 15 for the Spurs.
McCollum's 3-pointer put the Blazers up 73-60, their biggest lead of the game to that point. The team stretched the lead to as many as 18 points in the 38-point quarter.
The Blazers shot 53.6 percent from the floor for the game. The Spurs shot 42 percent.
Spurs: The two teams will meet four total times this season. The Spurs won last season's series 2-1. ... Chimezie Metu made his NBA debut. Metu was selected by the Spurs in the second round of the NBA Draft this past summer, after three seasons at USC.
Trail Blazers: Stauskas, acquired by the Blazers as a free agent in the offseason, grabbed the attention of fans with his performance in the opener and was treated with cheers when he came off the bench in the second quarter. ... Lillard finished with nine assists.
The Spurs: Visit the Lakers and LeBron James on Monday.
The Blazers: Host the Washington Wizards on Monday.
Boomers winning ugly on road to Rio redemption
Rio redemption is at hand. With their 82-70 victory over the Czech Republic, the Boomers will meet Spain in a semifinal to determine if a gold (or silver) medal is in play. All you have to do is win - win well, or win ugly - it's all the same.
The Boomers' road to a medal is now set
Australia managed to pip France at the FIBA World Cup, narrowly winning the game-within-the game against Rudy Gobert and setting up a path which avoids the USA until the final.
The Boomers and Lithuania: A rivalry forged over two decades
The intertwined histories of the Boomers and the Lithuanian national team in major tournaments is perhaps summed up with a nod and a smile, Warren Yiu writes.