OAKLAND, Calif. — With one stunning swing against Mariano Rivera, Marco Scutaro gave the Oakland Athletics their first series victory of the season.

Scutaro hit a three-run homer with two outs in the ninth inning, rallying the A’s to a 5-4 win over the Yankees yesterday.

The diminutive backup infielder drove an 0-2 pitch from Rivera off the screen just inside the left-field foul pole for the eighth game-ending hit of his career and second game-winning homer. The other came on August 25, 2004, against Baltimore.

“I wanted to go inside,” Rivera said. “It was in and over the plate.”

Rivera, who blew his first save chance of the season, got two quick outs in the ninth before Todd Walker singled for Oakland’s first hit since the third inning. Jason Kendall then walked, bringing up Scutaro.

The super-sub was in the lineup as a last-minute fill-in for injured second baseman Mark Ellis.

Oakland took two of three from the Yankees after going winless in its first three series. The first two games went to extra innings, taxing both bullpens.

Andy Pettitte overcame a rough first inning to pitch seven innings, outlasting Oakland right-hander Rich Harden, who left with tightness in his pitching shoulder.

Jorge Posada hit an RBI double in New York’s three-run seventh, when the Yankees also got consecutive sacrifice flies from Robinson Cano and Melky Cabrera.

Alex Rodriguez added a sacrifice fly in the eighth to make it 4–2. Nick Swisher made a difficult running catch of A-Rod’s drive, slamming into the center-field fence.

Pettitte allowed five hits and two runs — one earned. He struck out four and walked one. He gave up a first-inning run for the first time in 16 starts, which was the longest current streak among active pitchers.

Harden decided at the last minute to honor Jackie Robinson and wear no. 42 on the 60th anniversary of Robinson breaking baseball’s color barrier. Harden then dazzled through six innings with seven strikeouts.

Mike Mussina and Carl Pavano joined fellow Yankees starter Chien-Ming Wang on the disabled list yesterday, further depleting New York’s already taxed pitching staff.

“Nobody wants that,” Mussina said after cutting short his throwing session because of pain in his injured left hamstring. “We don’t have a choice. You just find a way to get through it and deal with it. It’s unfortunate. … Nobody’s having surgery. A couple of muscle pulls, a strain, we’ll be fine.”

After a pair of extra-inning games Friday and Saturday against Oakland, the Yankees called up righthander Chris Britton from Triple-A Scranton to give them a fresh arm in the bullpen for yesterday’s series finale against the reigning AL West champion Athletics.

New York manager Joe Torre said the club was discussing a couple of possibilities to take Pavano’s turn in the rotation tomorrow against the Cleveland Indians at Yankee Stadium. Left-hander Chase Wright was thought to be the leading candidate to be called up from the minors.