Willy Adames homered and drove in three early runs for the Giants, but they trailed 6-3 entering the eighth before coming back against reliever Tyler Kinley (0-3).
Adames, Heliot Ramos and Dominic Smith singled to load the bases with one out, and Casey Schmitt walked to bring in a run. Yastrzemski then lined a double off the right-center wall to tie it.
Tyler Fitzgerald laid down a bunt against Zach Agnos, and Schmitt slid around the tag of catcher Hunter Goodman with the go-ahead run. Schmitt was initially ruled out but the call was overturned following a replay review.
San Francisco added three insurance runs in the ninth on Wilmer Flores’ sacrifice fly, and RBI singles by Schmitt and Yastrzemski.
Goodman hit his 11th homer in the bottom half to give him three hits and two RBIs, but the major league-worst Rockies fell to 12-55 with their fifth straight defeat.
Tristan Beck (1-0) tossed three innings of relief for the win.
Adames and Yastrzemski each finished with three RBIs. Adames also had three hits and scored three times.
San Francisco’s previous eight games were decided by one run and its six prior wins came by that margin, one shy of the major league record for consecutive victories all by one run set by the 1927 Chicago Cubs.
Key moment
Colorado had two runners on when Orlando Arcia grounded back to closer Camilo Doval for the final out.
Key stats
The 1988 Atlanta Braves were the last team to play nine straight one-run games. … San Francisco has 17 wins this year after trailing by multiple runs. The only other teams since 1901 to do that in the first 68 games of a season were the 2000 Rockies (17) and 1979 Orioles (18).
Up next
Giants RHP Hayden Birdsong (3-1, 2.55 ERA) faces Rockies RHP Antonio Senzatela (1-10, 6.68) to wrap up the three-game series Thursday.