WASHINGTON – Bryce Harper has been in the majors so long, it’s easy to forget the Nationals outfielder is just 22 years old.

Especially when he does something like he did Wednesday, when he hit three home runs to power Washington to 7-5, series-clinching win against the Marlins.

Harper, who debuted at 19 and is already in his fourth season, became the 10th-youngest player in major league history to homer three times in a game. He did it a day after seeing his 20-game on-base streak ended, during which he .270 with a .460 OBP.

One of three active players to hit at least 55 homers before their age-22 season – Mike Trout and Giancarlo Stanton are the others – Harper entered Friday’s series opener against the Braves batting .265 with team-highs of eight homers, 20 RBIs, .416 OBP and .561 slugging percentage.

“He’s the perfect example of someone who just keeps getting better and better every year,” Braves manager Fredi Gonzalez said a few hours before Friday’s game. “He really does. Shoot, the sky’s the limit, because this guy can do a lot of stuff. Health is going to be a big factor there, but this guy – there’s nothing he can’t do, really. When he gets swinging the bat like he has been, you can’t get him out.”

Harper hit .288 with six homers, 23 RBIs and a .467 OBP in his past 21 games before Friday.

“He’s already played all three outfield positions, plays them tremendously,” Gonzalez said. “Runs the bases. And he’s only 22, 23?”

Harper has rubbed plenty of opponents – and even his own managers, on occasion – the wrong way in the past with a perceived arrogant attitude and immaturity.

“He’s a good player, and learning at the big league level,” Gonzalez said. “Because what did he have, two months in the minor leagues? It made him, not unapproachable, but more of a bad boy, you know what I mean? Trout’s (seen as) like, the greatest thing. But I think this guy’s a good kid. Watching him between the lines, he plays the game like you want it to be played.

“I know he got taken out of a game because he didn’t (hustle). You know what? That happens. It usually happens in the minor leagues and you take care of it in the minor leagues. But unfortunately, because he was 18 when he came up, he’s upset with himself, so he didn’t run, and he’s going to be in front of the media to do it.”