Saunders (6-8) allowed two runs on two hits with two walks and eight strikeouts for the Angels, who ended a two-game losing streak and posted their sixth win in nine games.
Rockies starter Aaron Cook (2-5) settled down after serving up a Matsui's sixth career grand slam in the first and held the Angels to one hit the rest of the way in a hard-luck, complete-game loss. Cook walked one and struck out three for Colorado, which lost for just the third time in its last nine games.
Fernando Rodney allowed one hit in one inning of scoreless relief and Brian Fuentes pitched a scoreless ninth to post his 13th save.
The Rockies' runs came on a Clint Barmes solo home run in the third and an RBI single by Michael Olivo in the fourth.