The Rockies blew a late lead for the second straight game. Colorado owned a 3-1 advantage heading into the eighth, but Nate Schierholtz tied it during that inning with a two-run double.
Felipe Paulino (0-2) was then called on by the Rockies to work the ninth in hopes of bringing about extra innings. Ross doubled to open the ninth and, after Aaron Rowand struck out, Sanchez singled on a 1-1 pitch to send home the winning run.
San Francisco closer Brian Wilson worked the top of the ninth in a tie game and picked up a victory that evened his record at 1-1. He has 10 saves on the season.
Colorado's Huston Street gave up two solo home runs in the ninth against Arizona Thursday when the Diamondbacks eventually downed the Rockies in 11 innings.