NEW YORK — Jason Giambi saved the New York Yankees, coming off the bench to hit a tying homer in the seventh inning and a game-winning single in the ninth for a 3-2 victory over the Boston Red Sox on Thursday.

Desperate to get back in the playoff race, New York salvaged the finale of a three-game series and won Boston's final regular-season game at Yankee Stadium.

Mariano Rivera (5-5) entered a tie game in the eighth and pitched 1 1-3 hitless innings for the win, helping the Yankees overcome another poor performance by Alex Rodriguez.

Booed vociferously all afternoon, A-Rod struck out three times and popped up with runners at the corners and one out in the sixth. The three-time MVP also had a terrible game Tuesday night, going 0-for-5 and grounding into a pair of double plays during a 7-3 loss.

This time, Giambi brought the Yankees back.

Rested against lefty Jon Lester, Giambi pinch hit with two outs in the seventh and connected for a two-run homer off Hideki Okajima that tied the score 2-all.

With the bases loaded and one out in the ninth, Giambi lined Jonathan Papelbon's 0-2 pitch into center field and was mobbed by jubilant teammates at first base.

Finally showing some vigor, New York moved within six games of the Red Sox, who lead the AL wild-card race. A series sweep by Boston would have left the Yankees eight games back with 29 to play — perhaps too steep a hill to climb.

The Yankees haven't missed a postseason since 1993, though their chances this year still look bleak.

The Red Sox fell to 285-484-4 at Yankee Stadium. New York will move next year into a $1.3 billion ballpark being built across the street.

Babe Ruth and the Yankees opened the current stadium by sweeping a four-game series from Boston in April 1923. Eighty-five years later, the Red Sox tried to return the favor.

Looking for its first sweep in the Bronx since April 2004, Boston got a fine effort from Lester but couldn't solve old-pro Mike Mussina or New York's bullpen.

After two comfortable wins by the Red Sox the previous two nights, the teams played the kind of tense, back-and-forth game that has marked their long rivalry.

Xavier Nady opened the ninth with a single off Justin Masterson (4-4). With one out, pinch-runner Brett Gardner stole second and Hideki Matsui was intentionally walked.

Masterson walked Ivan Rodriguez, loading the bases and bringing on Papelbon.

Lester was working on a four-hit shutout when Cody Ransom doubled with two outs in the seventh, chasing the lefty after 119 pitches.

Giambi's foul popup on Okajima's first pitch faded just enough to land on top of the dugout, and the slugger drove the next delivery off the front facing of the black batter's eye in center for his third career pinch-hit homer and second this season.