Splitter was impressive in the victory, with the power forward grabbing 18 points and 14 rebounds to help support Tony Parker's total of 20 points for the Spurs away from home.
"He's really a hard-working, night after night, kind of guy," Popovich told reporters.
"He's not a great athlete, but he's smart and does his work very early. He's always in good position and gives it unbelievable effort. He's been very important for us."
The result sees the Spurs sitting in first position in the Southwest Division with a record of 53-16 for the season.