The youthful, energetic Raptor who awaits old man Paul Pierce

TORONTO — For two days now — or actually for two sessions with inquiring-mind media types — the Raptors have addressed all sorts of questions about their youth and athleticism against the experience of the Methuselah-like Nets in the first-round playoff series.

“Our speed, athleticism and energy,” Raptors coach Dwane Casey said Friday when asked for Toronto’s best asset. “The ability to play a little faster than they can. It’s going to be who can impose their will on the other team.”

And there are lots of spots where the Raptors would like to be doing that imposing, but maybe none more than in the matchup between Toronto’s 26-year-old help-defender deluxe Amir Johnson and the Nets’ been-there, done-that a lot 36-year-old veteran Paul Pierce.

“[Pierce is] a 4 that can space the floor,” Johnson said. “I’ve just got to be aware of where he is on the court and try to make him drive and take away his 3s because he doesn’t have as much of his lift — but he’s getting his legs back. He’s definitely a threat. One of the superstar guys in this league.”

And so Pierce will start on Johnson’s radar when the first-round series begins at 12:30 in Toronto on Saturday.

Johnson, claiming an ankle he turned Wednesday against the Knicks is “good,” is athletically gifted and at 6-foot-9, can get out to the perimeter. But that will leave a void guarding the rim — center Jonas Valanciunas has never been mistaken inside for Bill Russell.

Johnson is a lunch-pail sort, a good offensive rebounder and a terrific help defender — such a good helper that he said, “I feel like I guard everybody else but my man sometimes.”

The Nets went from disappointment to a serious playoff team when coach Jason Kidd adopted a smaller lineup, one that utilized Pierce at the 4. Now it’s time for Johnson to earn his keep against the guy who was Brooklyn’s leading scorer (19.8) in the four-game season series split.

“A tough matchup for both sides. Amir’s got to use his advantage on the boards and in the paint — his rebounding, his running the floor,” Casey said. “And Pierce is a handful because he handles the ball and he’s on the perimeter. But Amir’s done it before.”

Chuck Hayes, one of Toronto’s veterans (30 years old, 26 games of playoff experience with Houston) stressed Johnson can’t give Pierce anything, anywhere, at any time.

“He has to make every possession tough. That’s going to be a task, going against a guy who has probably seen every defense in the world,” Hayes said. “They’ve got a strength in playing small with Paul at the 4 because he stretches the floor. But our strength is on the offensive glass. In the playoffs, second shots can hurt you. If we can take advantage of them being small … and get second shots, that would be great.”