Stephen Drew and Willie Bloomquist added RBI doubles and Miguel Montero had a two-run single for the Diamondbacks, winners of eight in a row at home.
Young also singled, walked twice, stole a base and scored a pair of runs.
Saunders (5-6) allowed only a single to reliever Josh Roenicke in the fifth and solo home runs to Michael Cuddyer in the fourth and sixth en route to his first win since June 10.
Saunders struck out nine and walked one.
Edwar Cabrera (0-2), who was recalled from Triple-A Colorado Springs earlier on Tuesday, lasted only 3 1-3 innings and allowed two runs on four hits and four walks.
Colorado has lost three straight and six of seven.
Cuddyer's first homer gave the Rockies a 1-0 lead. He pulled the Rockies 4-2 with his second long ball.
The Diamondbacks answered in the bottom of the fourth when Young walked, stole second and scored on a double by Drew.
Bloomquist followed with a ground-rule double that scored Drew for a 2-1 lead.
Young's fifth-inning home run just over the Diamondbacks' left field bullpen made it 4-1.
Montero lined a two-run single to right in the seventh to extend the Diamondbacks' lead to 6-2.
NOTES: Saunders' nine strikeouts matched a career high. . During the