SAN FRANCISCO -- Facing one of his team's biggest games of the season and a choice among four current or former All-Star pitchers, San Francisco Giants manager Bruce Bochy made a head-scratching call on Friday night.
He went in a fifth direction.
Bochy handed the ball to long-relief specialist and spot starter Chad Gaudin. Ninety-two pitches later, nobody is questioning the genius of the man.
Making just his seventh start as a Giant, Gaudin shut out the Arizona Diamondbacks on three hits in seven innings and his teammates got to nemesis Ian Kennedy for all the runs they needed in a two-run first inning en route to a 2-0 victory over the National League West division leaders.
"The pitcher won it for us tonight," Bochy said after victory No. 1,497 of his managerial career. "I'm not surprised. He's always well prepared."
Buster Posey and Hunter Pence drove in runs in the decisive first inning as the fourth-place Giants opened what they consider to be a critical 10-game homestand by beating Kennedy (3-7) for the first time in 11 starts to move 5 1/2 games behind the Diamondbacks in the NL West.
The defending division champs ran their record to 7-3 against the Diamondbacks this season. The two teams will meet nine more times in the season's second half, including six more games in San Francisco.
"Huge. Any win in the division is huge," said Gaudin (4-1), who has posted a 0.77 ERA in his last four starts. "We started the second half off on a good note."
Gaudin, who joined the Giants' starting rotation after Ryan Vogelsong broke his right hand on May 20, remained unbeaten as a starter (4-0). He did it by once again dominating right-handed hitters, holding Arizona's hitless in 11 at-bats. The 30-year-old entered the game having held right-handed hitters to a .172 average.
Gaudin left for a pinch hitter after seven innings, having matched his season high with 92 pitches. He didn't walk a batter and struck out eight.
"He's very consistent," Bochy said. "That's why we let him go the first game (of the second half) here."
All three hits off Gaudin were singles. The Diamondbacks never advanced a runner past first base against him.
Miguel Montero had two of the three hits off the right-hander.
Santiago Casilla, the fourth Giants pitcher in the eighth, got All-Star Paul Goldschmidt to ground to shortstop with two outs and the bases loaded to preserve the 2-0 lead.
Closer Sergio Romo pitched a hitless ninth inning for his 22nd save.
"That was our one opportunity," Diamondbacks manager Kirk Gibson said of the eighth, an inning in which two hits and a walk loaded the bases for top RBI man Goldschmidt. "He hit the ball hard. It was just right at (Brandon Crawford)."
The loss was Arizona's 11th in its last 14 road games. It reduced the Diamondbacks' lead over the second-place Los Angeles Dodgers to 1 1/2 games in the NL West.
Failing to log his 50th career win for an eighth consecutive start, Kennedy held the Giants scoreless after a three-hit, two-walk first inning. He pitched six innings, giving up the two runs and five hits. He walked three and struck out three.
"They came out very aggressive," Gibson said of the Giants, who added to Kennedy's first-inning woes.
The former Cy Young Award runner-up has now allowed 17 first-inning runs in his 19 starts this season.
"He threw a lot better after that," Gibson said. "We had no offense going tonight."
The Giants out-hit the Diamondbacks 8-5. Pence and Brandon Belt had two hits apiece for San Francisco.
NOTES: All five Arizona hits were singles, snapping a string of 79 consecutive games with at least one extra-base hit. The streak had been the longest in the majors. ... Despite being 5 1/2 games behind the Diamondbacks, the Giants (28-20) have a far better record against NL West competition than Arizona (21-23). ... The Giants began the second half having played the most road games (51) in the NL. They get 37 of 67 at home to finish the season. ... Bochy announced before the game that he expects Vogelsong, out since May 20 with a broken right (pitching) hand, back in the starting rotation shortly after Aug. 1 and CF Angel Pagan, who underwent hamstring surgery June 25, back atop the lineup on or around Sept. 1. ... When the Diamondbacks return home Monday to open a four-game series against the Chicago Cubs, they'll be greeted by the "Luchador," a professional wrestler look-alike who Thursday was named the club's official mascot. The first 20,000 fans at the team's July 27 game against the San Diego Padres will receive Luchador masks.