SAN FRANCISCO (Interstat) — Nick Frasso pitched a scoreless inning of relief to earn his first major league win as the Colorado Rockies outlasted the San Francisco Giants 13-7 on Sunday afternoon at Oracle Park.

The Rockies, who have now won two of three in the series, improved to 50-74. The Giants dropped to 51-73. Frasso, who entered with a 0-1 record, worked the bottom of the eighth, allowed one hit and struck out two. Sam Hentges took the loss for San Francisco, falling to 1-5 after failing to record an out in the decisive sixth inning.

The game featured five lead changes and a total of 20 runs, with Colorado erasing a 7-6 deficit with a four-run sixth inning and then adding three more in the seventh to pull away.

Colorado’s offense came alive early. After the Giants grabbed a 1-0 lead in the first inning on Bryce Eldridge’s RBI single, the Rockies answered in the second. Adael Amador, who entered as a pinch-hitter and went 1-for-1, launched a three-run homer to right field to give Colorado a 4-1 lead. The shot scored Jordan Beck and Brett Sullivan, who had both walked.

San Francisco responded immediately in the bottom of the second. Drew Gilbert singled in a run and Rafael Devers followed with a three-run homer to right, his 25th of the season, to put the Giants ahead 5-4. Turner Hill added an RBI single in the third to extend San Francisco’s lead to 6-4.

Colorado tied it in the fifth. Amador worked a walk and Jake McCarthy also walked before Cole Carrigg doubled to left, scoring Amador. Mickey Moniak followed with a sacrifice fly to center, scoring McCarthy and tying the game at 6.

The Giants regained the lead in the bottom of the fifth. With two outs and the bases loaded, Buddy Kennedy walked to force in Bryce Eldridge, making it 7-6. But the Giants left the bases loaded when Christian Koss struck out.

That set the stage for Colorado’s pivotal bottom half of the sixth. The Rockies loaded the bases with walks to Troy Johnston and Jordan Beck plus a fielder’s choice that put Zac Veen on first. Brett Sullivan grounded out, scoring Veen, but the Rockies kept the inning alive. Amador walked to re-load the bases, and Jake McCarthy walked to force in Beck, tying the game at 7. Cole Carrigg was then hit by a pitch, forcing in Amador to give Colorado an 8-7 lead.

Mickey Moniak followed with a two-run single to left, scoring McCarthy and Carrigg. The ball was misplayed by left fielder Turner Hill, allowing Moniak to advance to second, and the Rockies emerged with a 10-7 advantage.

Colorado added three more runs in the seventh. Connor Norby singled, Jordan Beck walked, and Brett Sullivan homered to right, his seventh of the season, to stretch the lead to 13-7.

Devers finished 2-for-5 with a homer and three RBIs for the Giants, who out-hit Colorado 11-9 but could not overcome the late burst from the Rockies offense. Amador drove in three runs on his lone hit, while Sullivan also knocked in three. Moniak and Devers were the only other players with multiple RBIs, though Moniak’s three came on his single and a sacrifice fly.

Colorado’s bullpen kept San Francisco in check after the fifth inning. Zach Agnos was strongest among the Rockies relievers, throwing two scoreless innings and allowing two hits while striking out two. Jimmy Herget also pitched a clean inning with one strikeout. Trent Harris worked a scoreless eighth for San Francisco, allowing one hit and striking out two, while Jason Foley added a perfect ninth.

The game lasted 3 hours, 8 minutes in front of an announced crowd of 32,063.

The Rockies had dropped the opener of the series 7-1 on Saturday but bounced back with a strong offensive showing Sunday. The win was Colorado’s third in its past four games overall. San Francisco, meanwhile, has lost four of its past five.

Colorado’s next game is Monday at home against the Los Angeles Dodgers, while San Francisco travels to Cleveland for a three-game series beginning Tuesday.

The game’s most critical sequence came in the sixth inning when the Rockies turned a one-run deficit into a three-run lead. The inning included four walks, a hit batsman and Moniak’s two-run single, and it gave Colorado a lead it would not relinquish.

For the Giants, the loss wasted a solid start from their bullpen early, but the game turned when Hentges and the following relievers could not contain Colorado’s patience at the plate. The Rockies drew 12 walks in the game, contributing to their ability to keep rallies going.

Colorado’s final three runs in the seventh inning came after two outs, when Sullivan’s homer to right field put the game out of reach.

Notes: Colorado pitchers combined for eight strikeouts and 13 walks issued by San Francisco pitching. The Rockies were patient all afternoon, including five walks in the sixth inning alone.

Interstat’s game simulator had projected a final score of Colorado Rockies 4, San Francisco Giants 3. Interstat’s ELO system had projected San Francisco with a 62.50 percent probability to win. The Giants had been installed as a pregame favorite with a spread of minus 1.5. The total score of 20 runs went under the over/under line of 8.5.