Tampa, Fla. ? Jason Giambi needed just a few swings to prove what the New York Yankees already knew: He’s a perfect fit in pinstripes.

Giambi got off to a smashing debut for his new team, hitting a two-run homer in his very first at-bat and later launching a solo shot Saturday in a 6-3 victory over the Toronto Blue Jays.

“I set my expectation level a little high today,” he said.

Giambi went 2-for-3 and also made a nifty, backhanded pickup at first base on a throw bounced by shortstop Derek Jeter.

The first baseman exited after five innings to high-fives from his teammates and a standing ovation from the crowd of 10,205 at Legends Field.

“That’s certainly a statement, even if it is just spring training,” owner George Steinbrenner gushed.

Giambi, the prize free agent in the offseason, left Oakland to sign a $120 million, seven-year contract with the Yankees. The 2000 AL MVP carried high hopes from Yankees’ management and fans who have seen their team win four of the last six World Series.

“It’s my job to temper the excitement, to say it’s only one game and it’s only spring training,” general manager Brian Cashman said. “But it was pretty neat.”

Slowed by tightness in his left hamstring, Giambi did not play in the Yankees’ first two exhibition games.

“It was great to get out there and get a chance to play, move around the bases and swing the bat a little,” he said.

An energetic personality, Giambi always had a sense for drama when he played for the Athletics. The fact that he connected in his first at-bat  albeit a wind-aided home run to the opposite field  did not surprise his brother, Oakland outfielder Jeremy Giambi.

“The guy is amazing. Here he hasn’t touched a bat all winter and then the first time he does, he takes three swings and he’s locked in,” the younger Giambi said before the A’s played Anaheim at Phoenix.

“I’ve seen him do some amazing things with the bat. He left in the best shape of his life, he goes to a new team and hopefully he’ll have a year he won’t forget,” he said. “I still hope we go farther in the playoffs than they do.”

Jason Giambi drew a loud cheer when he stepped into the batter’s box to face Brandon Lyon in the first inning with Bernie Williams on second base and no outs.