ST. LOUIS — San Francisco Giants rookie Christian Arroyo has already had some memorable big league moments. He added perhaps his biggest on Saturday night.

Arroyo's two-run double broke a scoreless tie and the San Francisco Giants beat the St. Louis Cardinals 3-1 in 13 innings.

Arroyo's double off the wall in left field scored Buster Posey and Brandon Crawford and came on the 12th pitch he saw from Cardinals reliever Kevin Siegrist (0-1). Posey, Crawford and Eduardo Nunez had singled to load the bases, giving the Giants their first runners in scoring position in the game.

"He (Siegrist) did a great job for a lefty throwing at the inside part of the plate with authority," Arroyo said. "I just kind of went into battle mode and tried to stay as free as I could and not get locked up."

Mac Williamson followed with a sacrifice fly to score Nunez.

Giants starter Jeff Samardzija threw eight innings, scattering five hits and striking out eight. He threw 75 of his 105 pitches for strikes.

"He's pitching right now," Giants manager Bruce Bochy said. "He's got four pitches going and with command. First pitch strikes and quality strikes."

It was the fourth straight start that Samardzija didn't surrender a walk. He has 36 strikeouts during that span.

"I thought my fastball was there tonight, when I needed a strike, a quality strike, I could go to my fastball," Samardzija said. "The curveball too, I could throw my curveball for a strike and it just gave me another dimension."

Hunter Strickland (1-1), Derek Law and Josh Osich pitched in relief for the Giants, who won for the seventh time in eight games.

Mark Melancon earned his eighth save after allowing a run to score on a single by Stephen Piscotty.

The game was delayed by rain for 42 minutes after the 10th inning.

Cardinals starter Carlos Martinez pitched nine innings for the first time in his career, but fell victim to lack of run support. Martinez gave up two hits, struck out five and needed just 93 pitches to get through nine innings.

"This was probably his best start of his career and part of that was his trust in his defence and making pitches in the bottom," Cardinals manager Mike Matheny said. "He used everything, changeup was good and breaking ball was good. He had it all tonight it was just a shame we couldn't do anything with it."

Matt Bowman and Trevor Rosenthal each pitched a scoreless inning in relief for the Cardinals, who dropped their fourth straight.

Matt Carpenter led off the bottom of the ninth with a double, but was thrown out at third trying to stretch it into a triple, thwarting the best chance either team had of scoring in regulation.

Cardinals second baseman Kolten Wong left the game after three innings with left elbow discomfort. He was replaced by Greg Garcia.

Before the game the Cardinals traded first baseman Matt Adams to the Atlanta Braves for minor leaguer Juan Yepez and cash considerations. The Cardinals activated Piscotty from the 10-day DL.

HE'S STREAKING

Yadier Molina extended his hitting streak to 10 games with a single in the second inning. Molina is hitting .444 (12 for 27) in his career against Samardzija.

GIANT WEB GEMS

Crawford ran all the way from his shortstop position into medium right-centre field to make a sliding catch on a popup by Dexter Fowler leading off the bottom of the first.

Denard Span made a leaping grab against the centre field wall to rob Aledmys Diaz of an extra base hit in the bottom of the 10th.

TRAINING ROOM

Giants: IF Conor Gillaspie (back spasms) started a rehab at Triple-A Sacramento on Friday, going 1 for 3.

Cardinals: OF Jose Martinez (groin) will start a rehab Sunday at extended spring training and Single-A Palm Beach.

UP NEXT

Giants: RHP Matt Cain (3-1, 4.04 ERA) became just the 12th pitcher in franchise history to reach 2,000 innings pitched during his last outing. His 7.62 ERA at Busch Stadium is the highest in any ballpark where he has made multiple starts.

Cardinals: RHP Adam Wainwright (3-3, 5.31 ERA) is coming off his best start of the season with seven shutout innings against Chicago on Sunday. He will tie Al Hrabosky for 11th on the franchise games pitched list (329) and is 5-7 with a 3.27 ERA in 14 career games against San Francisco.

___

This story has been corrected to fix final score to 3-1 in headlines, summary.