SAN FRANCISCO -- The standings don't tell the story of the San Francisco Giants vs. the San Diego Padres.

The pitchers do.

Two games into a three-game series at AT&T Park, the fourth-place Padres are dominating the first-place Giants. San Diego cruised to a 7-2 victory Tuesday night.

For the second consecutive game, the Padres ran up the score against a Giants starter. On Monday, they dropped a six spot on Matt Cain, and they scored six more off Tim Hudson on Tuesday. This is a Padres team that ranks last in the majors in several offensive categories, by a wide margin, including runs scored.

While Cain and Hudson got beaten up, San Diego's rookie starters stifled the Giants, who have lost 11 of 14 and dropped another game in the NL West standings to the second-place Los Angeles Dodgers, who are three games back after beating the Kansas City Royals 2-0.

It is the Giants' tiniest division lead since May 22.

A night after Odrisamer Despaigne blanked the Giants over seven innings in his major league debut, Jesse Hahn (3-1) was perfect through four innings and lasted six, giving up two runs on four hits and a walk while striking out eight.

With the score 6-2 and the game in the bullpen's hands, Tommy Medica hit his first career pinch homer in the seventh inning, a solo shot off Javier Lopez. The Giants made two errors, were out-hit 12-5 and didn't pose any threats once Hahn exited.

With Wednesday's matinee to go, the Padres clinched their first series win in San Francisco since Oct. 1-3, 2010. They played 10 series in a row without winning one. Outscoring the Giants 13-2 in the series, the Padres are oozing with confidence approaching Wednesday's finale that pits San Diego right-hander Ian Kennedy against San Francisco right-handerTim Lincecum.

A couple of themes remained intact through the early part of the game. The Giants kept struggling at the plate, and Hahn kept throwing zeros. Hahn entered the game with 13 consecutive scoreless innings, a string that reached 17 before the Giants scored in the fifth on left fielder Tyler Colvin's groundout.

Hudson gave up the game's first run in the third inning on right fielder Will Venable's sacrifice fly, scoring center fielder Cameron Maybin. The speedy Maybin went first to third on Alexi Amarista's single to center even though center fielder Gregor Blanco had the ball as Maybin rounded second.

The Padres scored twice more in the fifth on Amarista's double and Venable's groundout -- both unearned due to second baseman Joe Panik's error -- and three more times in the sixth, an inning featuring Amarista's bases-loaded single.

Amarista, San Diego's second baseman, finished 3-for-4 with three RBIs.

Hudson (7-4) lasted 5 2/3 innings, and he was charged with six runs (four earned) on nine hits and two walks.

It could have been worse. The Giants turned three double plays for Hudson in the first four innings.

Hudson lost at home for the first time this season. Before Tuesday, the Giants were 7-0 in his home starts, and he was 5-0 with a 2.16 ERA at AT&T Park. Dating back to his time with the Braves, his team had a 16-game home winning streak in games Hudson started. The last home loss for Hudson came Sept. 28, 2012, against the Mets.

NOTES: Giants CF Angel Pagan (lower back soreness) was out of the lineup for the eighth straight game, and management still is debating whether he will go on the disabled list. ...Giants 1B Brandon Belt (broken left thumb) will begin his rehab assignment Thursday. ...RHP Odrisamer Despaigne will remain in the Padres' rotation, manager Bud Black said. Despaigne threw seven scoreless innings Monday in San Francisco during his major league debut. ... San Diego 3B Chase Headley (herniated disk) returned to the lineup for the first time since June 19. ....OF Hunter Renfroe, 22, and RHP Tayron Guerrero, 23, will represent the Padres in the Futures Game. LHP Edwin Escobar, 22, will represent the Giants.