NEW YORK – Sometimes the best lessons are also the ones learned hardest, with pain and disappointment as the merciless tour guides.

Such is the plight with Daniel Bard, who was coasting along with otherworldly ease and precision during his rookie year working out of the bullpen for the Red Sox. The 24-year-old right-hander is blessed with free, easy velocity that touches 100-mph and a hard breaking ball that’s gained in life and movement since teaming up with pitching coach John Farrell. The tools are there.

Bard had even set a modern franchise standard by not yielding a homer in his first 27 big leagues games, which made him the first Red Sox pitcher to do so since the Teddy Ballgame Era days of 1954.

But all of that quickly changed last week when Rays third baseman Evan Longoria touched him for a game-tying home run that eventually led to an extra-inning defeat at the beginning of Boston’s current six-game losing skid.

Bard didn’t have any time to really take a breath and regroup, though, as he was in two more big spots at Yankee Stadium this weekend. The young righty managed to wriggle free of damage in his first appearance during Friday’s epic 15-inning game, despite a slight shoulder movement out of the stretch that resulted in a balk call to put runners on second and third.

He wasn’t as lucky on Sunday night, however. He took to the mound in the eighth inning, armed with a fresh 2-1 lead courtesy of a huge Victor Martinez home run to left field. It didn’t last long, as the seemingly bulletproof rookie allowed back-to-back home run balls in an eventual 5-2 loss at Yankee Stadium.

Bard was armed with his filthy-good stuff and quickly chalked up two outs in the inning, as Hideki Okajima and Jonathan Papelbon warmed up behind him in the bullpen.

But class was suddenly in session for the young reliever.

The youngster fell behind Johnny Damon 1-0 and went down-and-in with a 98-mph fastball to the lefty swinger who delights in the low fastball. The outfielder-formerly-known-as-Captain-Caveman pounded Bard’s offering into the Yankees bullpen in right-center field.

Tie ballgame. Bard had wilted in a big spot.

“The count was in Damon’s favor, 1-0, and I think I’ve got a little comfortable that guys are going to swing and miss on balls down the middle in those counts,” said Bard, who tripled his home runs allowed output in short stint at Yankee Stadium. “I think I got a little comfortable. It wasn’t a terrible pitch, but that’s where he likes it. It was down and in, and he sat on it and did a good job with it.”

One batter later Bard missed high with his slider-ish curveball. First baseman Mark Teixeira slammed the hanger into the second deck of the right field bleachers. That’s three big games and three rocky performances in the last week for the rookie, with two of those games resulting in blown saves – the first two of his big-league career -- and lingering questions about the home run balls served up.

It was clear that Bard knew how important the game was for his team, but he vowed there will be other teams when he will come through in the big moment.

“They weren’t terrible pitches. It’s part of baseball. We’re going to have ups and downs. I’m not perfect,” said Bard. “I had a string of a lot of good innings in a row and I knew it was going to come to an end eventually. What better way than here against the Yankees? No, like I said there are ups and downs.

“I’m not going to change everything because they weren’t terrible pitches. It’s two really good hitters that sat on the right pitch at the right time.”

With Bard’s confidence sufficiently built-up after parlaying his season-long excellence into a prominent setup role in Boston’s bullpen, a few misfires like the Longoria home run ball and the New York meltdown will perhaps serve as the finishing lessons for a bullpen master class.

The 6-foot-4, 200-pounder has learned everything he’s possibly going to absorb while averaging 11.57 strikeouts per nine innings and limiting hitters to a puny .197 batting average out of the pen. Bard’s last great achievement will be giving it up at the most paramount of moments – such as last night’s dagger into the heart of Boston’s AL East chances – and then returning more dominant than ever when he’s next called upon to put out a five-alarm Sox fire in the Bronx.

Perhaps the ultimate respect for Bard is that closer Jonathan Papelbon – who knows what it’s like to fail as the last line of bullpen defense while every eye watches intently – didn’t feel the need to say anything supportive to his young understudy after the fact.

“He’s a professional, man. He knows what to do,” said Papelbon. “This might sound funny, but this could turn out to be a positive thing for him in the long run. You learn a lot more (as a reliever) on a night like tonight than you do when everything is going smoothly.”

Perhaps some day soon Sunday night’s faltering will be looked upon as the final stage in Bard’s development into the essential setup man. But on Sunday, that was a lesson that seemed difficult to appreciate.