Tony Parker had 18 points and eight assists and Duncan had 15 points and eight rebounds and San Antonio rolled to a 111-90 victory over the Golden State Warriors on Wednesday night, extending the Spurs' franchise record winning streak to 19 games.
''They're playing amazing right now,'' Golden State guard Stephen Curry said. ''That's the best in the league right now.''
San Antonio (59-16) extended its league-leading record to four games over the Thunder (54-19) ahead of their matchup Thursday night in Oklahoma City.
Spurs coach Gregg Popovich was able to rest his core players with his team leading by as many as 26 points and never trailing after the opening three minutes.
''Our minutes stayed low and it's just like Pop likes it, so we'll see what happens tomorrow (against Oklahoma City),'' Duncan said.
Duncan played only 20 minutes and Parker 28. Both sat out the entire fourth quarter.
After struggling with his outside shot for much of the season, Duncan is regaining his soft touch just in time for San Antonio's 17th consecutive postseason appearance.
He finished 7 for 11 from the field, including 6-for-7 shooting in the first half on a series of soft jumpers, bank shots and a dunk.
''The Big Dog is always a key for us,'' Spurs reserve post Jeff Ayres said. ''We pretty much go as he goes. If he's hooping like that, it just lifts everybody up. It opens everything up for everybody else.''
Manu Ginobili and Patty Mills scored 13 points apiece, Marco Belinelli had 12 and Kawhi Leonard 11.
San Antonio swept the four-game season series against Golden State and has won 31 straight at home against the Warriors, the Spurs' longest active winning streak against any team.
The ''Splash Brothers'' struggled offensively, especially in the first half against San Antonio's perpetual motion.
''Just the way they move the ball,'' Curry said. ''It seems like they're always on the attack. They force you to make decisions on both ends of the floor.''
Marreese Speights scored 22 points and fellow reserve Jordan Crawford added 16 points for Golden State.
With the Warriors missing Andrew Bogut, David Lee and Festus Ezeli, Speights provided the team with a needed boost inside. He was 10 for 16 from field and had nine rebounds in 30 minutes.
''Coach keeps giving me a chance, and I'm just trying to make the best out of it,'' Speights said. ''Coach is a good coach and he finds guys and gets the best out of them.''
Popovich found a way to do the same after screaming for a timeout 69 seconds into the game after a turnover and missed 21-foot jumper by Duncan put San Antonio in a 4-0 hole.
San Antonio responded to their coach's directions with a 14-2 run as Parker and Duncan essentially turned the team's fluid ball movement into a two-man game.
Duncan made his next four attempts on a tip follow, dunk, reverse layup and baby hook. Parker assisted on two of Duncan's baskets and made a 3-foot jumper, two free throws and finished with a layup and a 14-6 lead with 6:46 remaining.
''We didn't get off to a quick start,'' Duncan said. ''For the first couple of minutes we were kind of sputtering out of there, but we got some shots to go. (We got) some stops to go and kind of got ourselves a lead there.''
After shooting a combined 5 for 13 in opening half, the ''Splash Brothers'' found their range in the third quarter to rally Golden State.
They opened the quarter shooting 4 for 6, with Thompson hitting a pair of 3-pointers and Curry adding his only one of the game.
Thompson's second 3-pointer pulled Golden State within 71-61 with 6:23 remaining in the third. Speights hit a pair of free throws to cut the lead to 74-67 with 4:30 remaining.
San Antonio responded as it has throughout its winning streak, using player and ball movement to close the quarter on a 16-6 run following Thompson's 3.
''They're pros,'' Popovich said. ''They just kept playing. They tried to be solid. There's going to be runs in a 48-minute NBA game. With all the possessions, you're not going usually keep a lead like that. (Warriors) made a run and we responded well.''
NOTES: San Antonio has not lost at home to Golden State since a 108-94 defeat on Feb. 14, 1997. ... Spurs F Matt Bonner (right calf strain), F Austin Daye (mild left lat strain) and C Aron Baynes (fractured right rib) did not play, leaving the Spurs with only Duncan, Splitter and Jeff Ayres standing 6-foot-9 or taller. Popovich is unsure when Bonner will return. ... San Antonio Express-News writer Mike Monroe received the Phil Jasner lifetime achievement award from the Professional Basketball Writers Association.