There may be days when we're reminded Harper is a mere 19 years old, and absolutely overwhelmed by baseball's biggest stage. So far, though, he has made the hardest game on earth look easy.
"I think he showed tonight the stage is not too big for him," Nats reliever Craig Stammen said.
Cue the happy manager.
"What about the kid?" Davey Johnson asked after watching his Nationals score twice in the bottom of the ninth inning Wednesday for a 5-4 victory over the Diamondbacks.
Yeah, what about the kid, Davey?
"He was born for these situations," Johnson said.
Let's review Harper's fourth Major League game. Infield single in the second inning. Double off the wall in the fourth. Fly ball to center in the seventh. Double off the wall in the ninth.
"He's living up to the hype," Washington starter Edwin Jackson said. "There's a lot of pressure on him, but it seems like he's out there playing pressure free. He's showing why he is who he is."
Harper missed home runs by mere inches on both the doubles, but scored later in both innings. He barreled into D-backs catcher Miguel Montero in the fourth and slapped the ball out of his glove.
In the ninth, with the Nationals trailing by a run, Harper just missed the game-tying home run, then sprinted home when Ian Desmond went deep to finish it.
"I'm trying to bring some fire to the table and play the game I've known my whole life," Harper said. "Just trying to bust my butt."
Now for Harper's most spectacular moment of the evening. That came in the top of the sixth inning, when he ran down a Jason Kubel liner.
Or maybe the liner ran him down.
Whatever, Harper lost the ball momentarily in the lights, got it in his glove, and then lost it. He ended up grabbing the ball with his bare hand as he tumbled to the ground.
"I was wondering if people saw that," Harper said.
Mostly what people are going to be noticing is that Harper is hitting .385, that he's grinding out at-bats and hitting the ball consistently hard.
"He's probably more relaxed now than he was in Syracuse," Johnson said.
He means that Harper has been singularly focused on playing in the Major Leagues for the past several years. Now that Harper has arrived, he only has to do the things he has always done.
"He likes being up with the game on the line," Johnson said. "You can tell. He's aggressive. He makes 'em throw it over. He's trying to do some damage every time he swings it. It's fun watching."
Now about hitting Harper seventh in the order. How much longer is that going to last, Davey?
"I just asked the coaches, 'Is it too early?'" Johnson said, smiling.
And they said?
Best of all for the Nats is that their five-game losing streak was snapped. Not only was Harper part of a victory for the first time, but a team playing without two of its best hitters, Ryan Zimmerman and Michael Morse, had a night that ended with smiles all around and a clubhouse filled with music.
"Oh my gosh, unbelievable," Harper said. "To get this win tonight is huge."
At 15-9, the Nationals are holding on to first place in the National League East, a half-game ahead of the Braves with a big series against the Phillies at Nationals Park this weekend.
"It's nice to have music in here, and everyone loosened up a little bit," Desmond said.
"We're really playing our hearts out."
Richard Justice is a columnist for MLB.com. Read his blog, Justice4U. This story was not subject to the approval of Major League Baseball or its clubs.