San Francisco catcher Patrick Bailey is 18 games into his major league career, yet his Giants teammates are already displaying a considerable amount of trust in the rookie.

Bailey sparked a go-ahead rally in the eighth inning with a double off an 11-pitch at-bat and scored on Brandon Crawford’s tiebreaking RBI single to help the Giants to a 4-3 win over the St. Louis Cardinals on Monday night.

Mitch Haniger drove in two runs, and Wilmer Flores had three hits for the Giants, who have won five of seven. San Francisco, which took the opener of the three-game set, has won just two of nine series in St. Louis since 2013.

San Francisco manager Gabe Kapler allowed Bailey to call the pitches for starter Logan Webb for the first time this season.

The 24-year-old Bailey, who went 2 for 3 and raised his average to .317, came through with flying colors.

Bailey also threw out Jordan Walker trying to steal in the third inning with a bullet throw that landed right on the bag.

Haniger’s single to right field in the seventh inning scored Flores and tied the game at 3-all.

In the eighth, Bailey doubled with one out off reliever Chris Stratton (1-1) and scored on the hit by Crawford, who pitched one inning of relief on Sunday in a 13-3 win over the Chicago Cubs.

Paul Goldschmidt and Paul DeJong homered for St. Louis, which has lost 10 of its last 13 games.

Goldschmidt poked a two-run homer of Webb in the sixth inning, giving the Cardinals a 3-2 lead. DeJong connected on a solo shot off Webb in the fifth.

Bailey has 14 RBIs so far and is closing in on becoming the sixth catcher to have at least 15 RBIs over the first 20 games of a career. That mark dates to 1920 when RBIs became a statistic.

Haniger highlighted San Francisco’s two-run third inning with an RBI double that scored Thairo Estrada.

Webb (5-6) allowed three runs on seven hits over seven innings. He struck out six.

Giants reliever Tyler Rogers worked two-thirds of an inning, and Camilo Doval recorded his NL-leading 17th save in 18th chances by recording four outs. He got Goldschmidt to ground back to the mound with two on to end the game.

St. Louis starter Matthew Liberatore gave up two runs on seven hits over six innings.