McCollum finished with 25 points and Maurice Harkless added 19 off the bench for the Blazers, who were without starter Damian Lillard. It was Portland’s fifth win in seven games, and third straight victory at home.
According to Elias Sports Bureau research, Ginobili is the only player in NBA history to have multiple 20-point games off the bench at age 40 or older. He finished with 21 points in a victory over the Suns on Friday.
Trailing by as many as 12 points in the third quarter, Portland rallied to lead 101-94 on Harkless’ 3-pointer with 5:37 left. But Ginobili’s 3 gave the Spurs a 105-103 lead with 2:48 left. He added another to extend the lead to 108-105.
McCollum’s layup with 1:11 left gave the Blazers back a one-point edge, but he missed an off-balance jumper that would have given Portland some cushion.
After Kyle Anderson‘s free throws put San Antonio in front, McCollum came through with his floater that gave Portland the winning margin. Aldridge missed a jumper from out front as time ran out.
Spurs forward Kawhi Leonard sat out because of a partial tear in his left shoulder, coach Gregg Popovich revealed before the game.
Leonard sustained the injury during the Spurs’ 103-89 win Friday over the Phoenix Suns.
“It’s too bad because he was starting to get back into form a little bit after playing a couple of games,” Popovich told reporters. The coach said the Spurs would monitor the injury over the coming days.
The game against the Suns was just Leonard’s eighth appearance of the season after missing the first 27 games with right quadriceps tendinopathy.
The Blazers were without Lillard because of a right calf strain. Lillard missed four games because of a strained right hamstring but played in the last two, despite the calf injury.
Lillard leads the Blazers with 24.9 points and 6.3 assists per game. Shabazz Napier started in his place.
Napier helped spark Portland at the start and the game was tied at 27 to start the second quarter.
The Spurs led 53-48 at the half, led by Aldridge with 15 points. Jusuf Nurkic had 11 for Portland.
San Antonio extended the lead to double digits early in the third quarter. Aldridge’s layup extended it to 69-57.
Napier continued to stand out for the Blazers, who closed within 74-69 with Harkless’ 3-pointer. Harkless added a short jumper and a pair of free throws to pull Portland closer.
Napier’s layup gave the Blazers an 80-77 lead near the end of the third quarter but Davis Bertans hit a 3 to pull San Antonio back into a tie to open the fourth quarter.
Napier finished with 15 points.
Al-Farouq Aminu‘s 3-pointer gave the Blazers a 91-87 lead with 8:21 left, Portland’s largest of the game to that point.
Ginobili became the first player in his 40s to score 15-plus points in back-to-back games since Michael Jordan in 2002-03, according to the Spurs.
Spurs: San Antonio won the opening game of this season’s series with the Blazers 93-91 in Portland on Dec. 20. The third of the three meetings will be in San Antonio on April 7. … Aldridge played his first nine NBA seasons with the Blazers.
Trail Blazers: Nurkic had his ninth double-double of the season. He finished with 17 points and 13 rebounds.
Spurs: Visit Sacramento on Monday night.
Trail Blazers: Visit the Oklahoma City Thunder on Tuesday.
The Associated Press contributed to this report.