It might have gone unsaid in the Giants' clubhouse. In fact, manager Bruce Bochy demands that. Deep down, though, everybody inside understands that a mere series victory against the first-place Diamondbacks will be nothing but a glancing blow.

To land a real punch, the Giants need a sweep, a possibility that remains after they rode seven shutout innings from Chad Gaudin to a 2-0 victory at AT&T Park on Friday night.

"What a great way to start the second half," closer Sergio Romo said after he earned his 22nd save. "We just gained a game on our division leader."

And that is big news, because the Giants had not done so since June 30. They still remain 5 1/2 games back and seven games below .500, and the true threat in the National League West might be the second-place Dodgers, but any step closer at this stage is better than a step back.

Gaudin improved to 4-0 with a 2.23 ERA as a starter. He was given a 2-0 lead after the first inning and ran with it, holding the Diamondbacks to three singles and no walks over seven innings. He struck out eight.

Bochy then went all Tony La Russa in the eighth. Bochy used four relievers to face six batters in the stressful inning. Ultimately, in his first critical appearance off the disabled list, Santiago Casilla got Paul Goldschmidt on a 6-4 forceout with the bases loaded to preserve the 2-0 lead.

Romo followed with a 1-2-3 ninth, his 29th consecutive scoreless appearance against the Diamondbacks dating to 2010.

All the scoring happened after Ian Kennedy walked Gregor Blanco to start the first inning. Buster Posey hit a one-out, RBI double, and Hunter Pence singled home Posey on a two-strike, two-out pitch.

The real story was Gaudin, who has opened eyes with his strike-throwing consistency. As Romo put it, Gaudin takes the mound and says, "Here it is. Here is what I have," and for the most part, hitters have been frustrated trying to hit it.