NEW YORK -- Tino Martinez's swing and career have been revived in the friendly confines of Yankee Stadium.

Brought back to New York after three difficult seasons away, Martinez was expected to be just a 37-year-old insurance policy at first base behind Jason Giambi.

He wasn't a feared hitter with St. Louis or Tampa Bay and didn't show signs early this season that he could be again. The bat speed that made him an All-Star with the Yankees appeared to be gone.

But as Giambi's career continued to spiral downward, Martinez's playing time rose. Just when the Yankees needed Martinez, the fan favorite started to hit and hit and hit.

For five straight games, all Yankees wins, Martinez has homered.

The Yankees carry their longest winning streak of the season to the West Coast for a six-game trip that starts tonight in Oakland and continues in Seattle.

"I feel like I have a job to do, period," he said. "I am in the lineup to drive in runs and get my hits. That's how I look at it."

When Giambi was signed after the Yankees' World Series loss in 2001, Martinez was out of a job.

Now Giambi is on the outside looking in. After a lost season in 2004, wrecked by injury and illness, Giambi spent the offseason dealing with the steroid scandal.

With Giambi hitting only .195, Martinez has reclaimed his spot as the everyday first baseman and the potent lefty bat in the lineup. Martinez hit .300 on the homestand with five homers and 11 RBIs, and has seven homers in his last eight starts.

"It just puts a smile on your face what he's done," Yankees manager Joe Torre said. "We feel pretty good about ourselves as a team again."

The barrage started last Saturday with a solo shot off Oakland's Joe Blanton. Martinez followed that with a three-run homer on Sunday. Once the Athletics were out of town, he set his sights on the Seattle Mariners.

A two-run homer on Monday gave the Yankees the lead. Another two-run shot the next day was the big blow in a five-run inning. Martinez finished the 5-1 homestand on Wednesday with a three-run shot off Matt Thornton that found the short porch in right field and tied the game at 9-9.

"Not only are they home runs, but they've been big home runs to win big games for us," said third baseman Alex Rodriguez, who leads the American League with 11 homers -- two more than Martinez. "Five in a row, so hopefully he can keep that going."

Not coincidentally, Martinez's power surge began just as the Yankees started to turn around their dismal start. New York (16-19) hadn't won as many as three in a row before this five-game streak.

He is three short of tying hitting coach Don Mattingly for the team record and the major league mark of eight straight games with a homer. This is the longest streak by a Yankee since Mattingly set the record in 1987.

Not bad for a guy who heard talk that he was washed up.

He never really fit in with St. Louis and hit only 36 home runs in the two seasons that spacious Busch Stadium was his home ballpark. Last year in his hometown of Tampa, Martinez had 23 homers and 76 RBIs.

That was not quite up to the standards he set while with the Yankees. Over the past 10 seasons, only three first baseman have posted more extra-base hits than Martinez.

With Giambi's health and playing status uncertain heading into this season, it made perfect sense to bring Martinez back to New York as a free agent -- just in case.

He signed on New Year's Eve, expecting to play only three or four times a week and hoping to add another title to the four championships he won during his first stint with the Yankees.

"He comes ready to play every day," said Jorge Posada, who hits behind Martinez in the lineup. "He doesn't say much, but when he says it, you've got to listen. Tino is a big part of winning championships because he's a leader and enjoys winning.

"I think having him around just brings that positive attitude again."

In his first tour of duty in the Bronx, Martinez overcame the tough task of replacing Mattingly at first base in 1996.

For the next six seasons, Martinez won over Yankees fans with clutch hits in critical games.

Martinez hit a grand slam in Game 1 of the 1998 World Series against San Diego, slammed a tying homer off Arizona's Byung-Hyun Kim with two outs in the ninth inning of Game 4 in 2001, and recorded at least 25 home runs and 105 RBIs in five of those six years.

And now Martinez is the talk of the town again, especially among those in the stands who chant his name as he circles the bases and continue cheering until he comes out for a curtain call.

"I have a lot of confidence," Martinez said. "I feel good at the plate. I'm having good at-bats and I'm seeing the ball well."

And everyone is noticing.

"It's incredible," Rodriguez said. "I asked him if it was that easy. He must be seeing it real well."