When it’s there, the Suns appear to be the NBA’s best team. When it’s not, opponents gleefully line up for layup drills that harden the opinions of the team’s skeptics. “It” is Amaré Stoudemire’s interior defense.

It was there during 15- and 17-game win streaks.

It wasn’t so much when the Suns looked like an ordinary team for much of the post All-Star game schedule.

And it’s been back for the Suns’ two playoff wins over the Lakers.

Stoudemire had four blocks, nine defensive rebounds and several altered shots in Tuesday’s 126-98 rout of Los Angeles in Game 2.

The exclamation points came on two early spectacular blocks of Kobe Bryant and Lamar Odom — defensive gems that set the stage for the Suns to explode and the Lakers to wilt.

As much as any other factor, Stoudemire’s defense in the paint may determine whether the Suns win their first NBA title.

But Stoudemire’s defense is far from a given.

Less than a week ago, as the Suns began to prepare for the playoffs, Steve Nash suggested Stoudemire’s defense had been lacking as the season wore down, ”But I have confidence in him going forward.”

“He might have gotten tired,” Suns coach Mike D’Antoni added.

“I played him a lot. And he didn’t play last year.

“A lot of people fade during the year. He’s got his energy back and he’s right back playing at the level he was (during the winning streaks).”

Stoudemire said he’s been studying and preparing, and he’s come to realize, “That’s what we need, that interior defense where you alter shots, block shots and come up with turnovers.”

It helps that he enjoys this, even if it’s taken years for him to put it together.

“Being a young player, defense is something you have to work on,” he said.

“It’s the hardest thing to do.”

But do it he must, if he wants to be recognized as an all-time great.

And now is as good a time as any.

“The playoffs are where superstars are born; it’s that simple,” he said.

“The regular season is full of stars, but there are only superstars in the playoffs.”

Stoudemire said he “loves” to block shots, recalling that he once blocked 10 in one game as a rookie and that the skill is only now coming back after last year’s absence.

He even acknowledged that, “Blocking a shot is more effective than a dunk” in that it “creates more of a statement in the game.”

“It takes a defensive stand and lets the other team know there’s an inside guy who’s trying to block all the shots, so be careful.

“Now they’re thinking about altering their shot when they drive to the basket.”

Stoudemire’s defensive awareness would be the finishing touch on a journey back from microfracture surgery 18 months ago.

Just six months ago — back in training camp — when his progress was viewed as disappointing internally, D’Antoni was starting to openly worry about him.

“The whole franchise kind of depended upon him. My job security depended on him,” D’Antoni said.

“If he couldn’t come back as the player he was, we’ve got a 'max’ player who can’t perform at a 'max’ level.

“So you worry about it.”

The team’s medical and training staff always believed he’d be fine, so, “We didn’t panic,” the Suns coach said.

But privately, “You say, 'Oh my God, what are we going to do?’”

In the end, Stoudemire came through with his rehab.

Then his explosive offense re-emerged.

Now, his defense is better than ever. Much of the time.

All he needs to do is put it together every game, and the Suns believe they can finally can reach their goal.