The five teams in the National League West were separated by only 4 1/2 games beginning Friday's action and Colorado was closest to the division-leading Diamondbacks.
Arizona got off to a good start in the mid-season showdown with Skaggs (2-1) shutting down the Rockies in his 10th major league start.
Skaggs gave up a first-inning single and did not allow another hit until the seventh. He walked only one and struck out five. J.J. Putz finished off the shutout with a perfect ninth in a non-save situation.
A.J. Pollock scored Arizona's first run in the opening inning on a wild pitch. Paul Goldschmidt singled in a run in the third, doubled home another in the fifth and Aaron Hill delivered a two-RBI in the seventh.
Jorge De La Rosa (8-5) took the loss, giving up three runs on seven hits in 5 1/3.