Two months into his rookie season, Draymond Green, then a Warriors reserve, got a crack at defending LeBron James. It was December 2012, in Miami, and James was rolling.

With Green on him, James failed to score twice. After a missed jumper and a turnover, James backed Green down and drew a foul. Then he yelled at Green.

“He said, ‘You too little,’ and I hate when people say that to me,” recalled Green, generously listed at 6-foot-7. “So I said something back to him. I think that’s where I gained respect. And it’s mutual.”

It was the first sign of the player we’ve come to know: a second-round draft pick with the bravado to trash-talk the best player in the world — and holding his own, too. That spirit is infused into the DNA of this Warriors squad now in the NBA Finals.

So the challenge of defeating James, now with Cleveland, is more exciting than intimidating. And Green already has done it once. That night in Miami, he hit the game-winning shot.

This is why you can feel good about the Warriors’ chances even though they are facing an all-time great. The Warriors don’t back down from any challenge. Green won’t let them. Whether he’s barking encouragement to his teammates or setting an example of resilience and defiance, the Warriors are game.

That belief is the foundation of a defense that has shined for the better part of this postseason. The Warriors conquered the brutal Western Conference during the regular season. They corralled the exceptional talent of Anthony Davis. They survived the physicality of Zach Randolph and Marc Gasol. They contained the explosiveness of the James Harden and Dwight Howard.

Now the only thing between the Warriors and the NBA title is King James, who is motivated to cap his storybook return to Cleveland with the franchise’s first title.

The Warriors have the better team. They should win this series. If they don’t, the most likely reason will be that LeBron’s greatness negated the Warriors’ superior depth and advantage at multiple positions. So the Warriors need to keep James in check.

And Green, runner-up as the league’s defensive player of the year, intends to lead the way, physically and mentally.

“That’s always been my mindset,” Green said. “If I am the so-called heartbeat of this team, then that’s my job — make sure we’re ready mentally for the challenge. This team should mirror my mindset, mirror my passion, or I can’t call myself a leader.”

With a championship at stake, the Warriors aren’t likely to need much verbal prodding from Green. But they will need his bravado and defensive acumen to pull off one of the most difficult challenges in NBA history: containing James.

The problem with James is that he doesn’t just win his matchup. He elevates his entire team, so when he plays well, usually those around him do the same.

The Warriors have multiple players to throw at LeBron. Green or Harrison Barnes could start on him. It’s likely Andre Iguodala will be called upon too.

But they all have a weakness the 6-8 James can exploit. Barnes isn’t savvy enough defensively to thwart a talent like James. Iguodala has the savvy but gives up at least two inches and 30 pounds to the King. Green has the strength to resist James, but James has a quickness advantage.

“Obviously it’s LeBron, but we didn’t just stumble here or wake up one morning and found ourselves in the Finals,” Green said. “We are here for a reason. There will be no shortage of confidence because we’re playing LeBron.”

The question is whether the Warriors choose to make James a scorer or devote multiple resources to slowing him and risking opening the door for his teammates.

James is shooting 42.6 percent from the field in the playoffs, and just 17.6 percent from 3-point range. He is third in scoring in the playoffs (27.6 points per game), but he is averaging the most shots (24.9 attempts per game). Still, James is as dangerous it gets, which is why he has been more productive on offense than even Stephen Curry in these playoffs.

And the Warriors know the one time they faced him this year, James dropped 42 and beat the Warriors in Cleveland. James missed the other meeting while resting injuries.

The pieces are there, though, and coach Steve Kerr and his staff have shown they know how to maneuver them for the desired results. Even if it takes a game or two, the Warriors usually figure something out.

“Obviously, we’ll go with the game plan,” Green said. “Back in the day, the NBA was like chess. You make a move, I make a move. That’s what coach Kerr reminds me of. Our coaches put in the work and we trust them. That’s worked all year, going with the game plan.”

If the plan calls for Green to take the challenge of James, he’ll be game. Just as he was that night in Miami three years ago.

Read Marcus Thompson II’s blog at blogs.mercurynews.com/thompson. Contact him at mthomps2@bayareanewsgroup.com. Follow him at Twitter.com/thompsonscribe.