West hit 9-of-12 shots from the field and his 20 points were four short of his season's best. He played just 27 minutes.
Indiana recorded its ninth win in 11 games and avoided back-to-back losses for what would have been only the second time this season.
Washington had won two in a row and was trying to equal its high-water mark of the campaign by reaching .500.
Indiana shot only 44 percent from the field, but dominated the backboards.
Bradley Beal led Washington with 17 points.
Ray Liotta sues skin care company over use of likeness
Millions of Getty images now available for free via embed tool