Indiana won its third in a row and improved the best record in the NBA to 31-7. The Pacers have lost only once at home all season.
Stephenson hit 10-of-17 from the field as part of Indiana's 50-percent shooting performance. Paul George added 25 points.
Martin played just seven minutes and missed the only shot he attempted. Stoudemire managed eight points in 14 minutes before he was injured. Carmelo Anthony led the Knicks with 28 points.
After winning five in a row, New York has dropped two straight -- both of the setbacks coming on the road. The Knicks will play their next eight games at home.