NEW YORK -- Making his first start of the new season, Mike Mussina did exactly what the Yankees had optimistically predicted he would -- keep his club in the ballgame while getting past the fifth inning.

That was all well and good for their future plans, but it came on the wrong night. Alex Rodriguez belted a long two-run homer, but the Yankees managed little else off Toronto starter A.J. Burnett, suffering a 5-2 defeat at Yankee Stadium.

"I wasn't disappointed in it," said Mussina, who allowed four runs (three earned) in 5 2/3 innings. "It felt good throwing the baseball. I just made some mistakes, and they took advantage of it. If I have that stuff 30 times, I'll be fine."

Now in his final year under contract and facing an uncertain future, Mussina has taken on more of a leadership role, helping to mentor some of the club's young pitchers and providing a sounding board for their inquiries.

Happy to have him as half-mentor, half-hurler, the Yankees are still curious as to what Mussina will provide for them, one year after he temporarily lost his spot in the rotation after a string of subpar outings.

The 39-year-old right-hander used his curveball as a go-to pitch for most of the evening, but he lost it on occasion as well, such as one flat sixth-inning offering that skimmed Frank Thomas' jersey.

"I thought he used his breaking ball well, and I thought his fastball was pretty good tonight," manager Joe Girardi said. "I thought he was locating well. I liked what I saw."

It was an evening when the Yankees were essentially handcuffed by one of Burnett's better performances. Since joining the Blue Jays, Burnett's biggest difficulty has been remaining on the field, having served four stints on the disabled list after inking a deal prior to the 2006 season.

He looked plenty healthy as he dispatched the Yankees lineup, though, limiting New York to two runs and five hits in six-plus innings. Rodriguez's homer, the 519th of his career and his first following a 2007 MVP campaign, came on Burnett's final pitch.

"I hit that ball as good as I can hit it," Rodriguez said. "I was fortunate. You never know with this weather. ... [Burnett was] very impressive. A guy that's throwing up in the mid-90s and is able to throw his curveball for strikes at will, that's a handful right there."

Facing Mussina, Toronto scratched out a run in the first inning on three consecutive singles, none of them particularly hard-hit, scoring as Alex Rios' bloop to shallow right brought home David Eckstein -- Rios' first of two RBIs.

Vernon Wells clubbed his first home run of the year, a two-run shot to left, in the third, and Toronto's fourth run scored on Aaron Hill's RBI single, coming on Mussina's 91st offering.

It was Wells' home run that Mussina would rue most, particularly because it immediately followed a two-out walk to Rios after he'd lost him from an 0-2 count.

"Probably the worst one I threw all day," Mussina said. "It ended up in the middle of the plate, and he hit it out of the park."

Mussina allowed eight hits, walking two and striking out two before yielding to reliever LaTroy Hawkins, who allowed a run in the seventh in his Yankees debut.

In hindsight, Mussina acknowledged the mismatch of comparing his numbers with Burnett's.

"It's tough when the other guy is throwing the ball as well as he was," he said. "He's got really good stuff. When he's on, he's as tough as anybody, and if he can stay healthy, he can have great years."

Held quiet for most of the first eight innings, the Yankees did have one last gasp in the ninth inning facing Jeremy Accardo. Derek Jeter opened the inning with an infield single that second baseman Hill knocked down but couldn't grip for a throw, and Bobby Abreu followed with a broken-bat single to shallow center.

That brought up Rodriguez as the potential tying run, but he struck out, and Jason Giambi was retired on a deep fly ball to left-center field that many who remained in the ballpark thought would be headed for Monument Park. Watching from the Yankees' bench, Girardi wasn't fooled.

"Not tonight," he said. "It's a long ways when you're going opposite field here as a left-handed hitter."

Giambi's loud out tracked down, Accardo retired Robinson Cano first-pitch swinging on a pop fly to left to end the game.

Through the season's first 17 innings, the Yankees' vaunted lineup has managed a grand total of five runs, but the consensus seems to be that was a credit to Toronto's hurlers more than anything.

"Their pitching staff is probably the best, top to bottom, in the game," Johnny Damon said. "I'd put them up against anybody."

Giambi had an eventful evening in the field, hours after Girardi reiterated that he anticipates the 37-year-old will play regularly defensively. Giambi booted a first-inning grounder and also fell into the photo box chasing a sixth-inning popup, but he also made a nifty sprawling stop to record a putout and save Jeter a throwing error.

It wasn't the same celebratory scene as Tuesday's final home opener, just No. 80 on the countdown board in right-center field, a refrigerated affair that the Yankees will sock away and try to trade for warmer memories by the next evening.

"You can't have it the way it was last night every night," Mussina said. "It's not possible."