MORNING BRIEFING

They gave him the key to the city and he treated it as if it were the key to the minibar.

That about sums up Jason Giambi’s career in pinstripes, a seven-year party for him, the beginning of the end for the Yankees.

Which is why it should surprise no one, but outrage many, that upon the occasion of his return to Yankee Stadium last week for what turned out to be a rained-out game against Oakland, Giambi summarized his Yankees career as follows: “It was fun. I really don’t regret anything. Those things that people say went wrong, I see as a learning experience; just learn from it and move on.”

Those little things that went wrong, like getting caught taking steroids, or having to testify before the BALCO grand jury, or missing most of two seasons because of one phantom injury after another -- remember the “pituitary tumor” that somehow disappeared, or the “four-pound” weight loss accomplished through the elimination of fast-food burgers? -- clearly didn’t hurt Giambi a bit.

He has moved on, to a $5-million deal with the A’s, where he started, and where he now assumes a “mentor’s role” with their young roster while hitting a puny .227 with no home runs and five RBIs.

Meanwhile the Yankees continue to spin their wheels, plugging holes in their roster with wads of cash, a practice that began with the signing of Giambi.

“It’s exciting to come back where I started,” Giambi said in a 10-minute news conference that was breathtaking in its insincerity and side-splitting in its revisionist history. He compared the new stadium to the Titanic, although he was quick to add it probably wouldn’t sink, sort of acknowledged buckling under the pressure of playing here, and revealed that he kept his apartment in Manhattan and plans to spend some time here “doing things I didn’t get to do when I played here.”

The signing of Giambi to a seven-year, $120-million contract after the shocking loss to Arizona in the 2001 World Series began an addiction to the big-ticket free agent du jour, an out-of-control spending spree that continues to this day.

Technically, the signing of Mike Mussina to a six-year, $88.5-million deal after the 2000 World Series may have been the first shot, but with the Giambi signing, George Steinbrenner, drunk on four shots of championship Kool-Aid, was off and running.

Since then, the Yankees have spent a total of $1,466,012,054 on ballplayers. In return, they have won this many world championships: zero.

And one thing every one of those teams had in common was the presence of Giambi.

When he came here on that December day in 2001, he spoke of his dad’s love of the Yankees and Mickey Mantle, a player Giambi clearly thought he could emulate.

Turns out all he could match the Mick for was partying. For all his shortcomings off the field, Mantle played through terrible injuries and he did it with a corn-fed and beer-fueled 185-pound body.

Giambi arrived pumped up to an artificial 235, his biceps bulging and his belly rounded over a liver enlarged (but not by booze), put up pretty numbers and left behind barely a trace that he had ever played here.

And in the end, Giambi had the last laugh. He took much more from the Yankees than they got back from him, collecting every last dime owed him without delivering the one thing expected of him.

“Unfortunately, we didn’t win a World Series, which is what you want to do when you come here, but like I told everybody, to win those four World Series was something special,” Giambi said. “I know everybody expects to win when they come here, but that’s not an easy thing to do. Those guys made it look pretty easy, but they had an incredible team.”

Yeah, with role players such as Scott Brosius and Charlie Hayes and a blue-collar catcher named Joe Girardi and not a single guy hitting more than 30 home runs in one of the championship years.

Somehow, the Yankees got a look at Giambi with his gaudy numbers and gaudier tattoos and decided that was the way to go. They couldn’t have been more wrong and yet, they continue to stumble down that same tired road, the one that runs through Carl Pavano and Alex Rodriguez and now brings them CC Sabathia, Mark Teixeira and A.J. Burnett, a $423.5-million investment that, like the Giambi contract, can probably never pay for itself.

“I gave my heart and soul when I played here, no doubt about it,” he said. “Like you know, showing up every day, ready to play.”

Hey, what did you expect for your $120 million? A ring or something?