BOSTON -Al Leiter dropped into baseball’s noisiest rivalry and gave the Yankees a performance even they didn’t expect.

The 39-year-old left-hander rewarded New York just one day after being rescued from the scrap heap, pitching three-hit ball into the seventh last night to help the Yankees beat Boston 5-3 and pull within a half-game of the Red Sox in the AL East.

With four starters on the disabled list and a thin trade market for pitchers, the Yankees bought Leiter from the Florida Marlins – and cheaply, too – and halfheartedly put him in the rotation. He responded with eight strikeouts and three walks in 6 1/3 innings, allowing just one run in his first AL start since 1995.

Despite a two-run rally against reliever Tom Gordon and closer Mariano Rivera in the ninth, the Yankees won for the 10th time in 12 games to move a season-high eight games above .500. They have not been this close to first place since the first week of the season.

Boston has lost four of its last five to whittle away what had been a four-game lead in the division on July 6.Tim Wakefield (8-8) pitched his first complete game since 1998 and allowed just five hits, but they included two-run homers by Jorge Posada and Gary Sheffield, and a solo shot by Alex Rodriguez.

Johnny Damon doubled in the eighth to extend his hitting streak to 29 games – the longest in the majors since Albert Pujols went 30 games in 2003.Damon hit a long flyball that just eluded Gary Sheffield’s leap in right-center.

Gordon relieved Tanyon Sturtze and got Edgar Renteria and David Ortiz to pop up to the infield to end the eighth. Gordon gave up Manny Ramirez’s homer and walked Kevin Millar to start the ninth before giving way to Rivera, who had saved 22 consecutive games since blowing his only two against Boston in the first week of the season.

Trot Nixon hit a potential double-play ball to second, but Robinson Cano threw the ball into left field. Pinch-hitter Jason Varitek singled in a run to make it 5-3, then Bill Mueller blooped a single into right field to load the bases. Alex Cora followed with a sharp grounder to third to start a 5-2-3 double play, with the throw barely beating the batter at first. Damon then grounded out to second to end the game.

Leiter was 3-7 with a 6.64 ERA in 17 games for the Marlins before they designated him for assignment last week. Desperate for pitching, the Yankees acquired him and most of the cash to pay the $2.8 million left on his 2005 contract.

General Manager Brian Cashman conceded that he didn’t expect much from Leiter, but there was no better alternative. He was the 11th starter used by the Yankees this season – most in the majors, according to the Elias Sports Bureau.

Leiter went 16 years, 82 days since his last Yankees start, on April 26, 1989. It’s the longest gap for them since Babe Ruth went nine years, 107 days.