Jason Grilli was originally credited with the win following the Rockies' 12-7 victory over the San Diego Padres on Monday. But scorer Dave Einspahr switched around the winners Tuesday night after reviewing Rusch's effectiveness in pitching out of a fourth-inning jam.
Rusch went 2 2/3 innings, giving up four hits and two runs.
Rusch also pitched a perfect fifth.
With the change, Rusch is now 1-0 and Grilli 0-1.