Bryce Harper is safe at third as Diamondbacks third baseman Ryan Roberts covers the bag. (Jonathan Newton/WASHINGTON POST)

Twenty-five games into this season, the Washington Nationals are without, to name a few, their best slugger (Michael Morse), their best player (Ryan Zimmerman) and their closer (Drew Storen). Injuries, it seems, have come in droves. The Nationals are also without backup closer (Brad Lidge) and a utility player (Mark DeRosa) they coveted in the offseason. And the team’s best hitter so far this year, Adam LaRoche, was scratched hours before Thursday’s game against the Diamondbacks.

Yet 25 games in, the Nationals are 16-9, still good enough for first place in the National League East, thanks to a 2-1 win before an announced crowd of 19,656 on Thursday. And while the offense around him has fallen to chips and strains and tears, it’s the all-hustle, uber-talented 19-year-old Bryce Harper, called up to the major leagues only five games ago, who has produced during this dire situation.

His double down the left field line in the sixth inning drove in Ian Desmond, the winning run in a well-pitched duel between starter Ross Detwiler and Diamondbacks right-hander Ian Kennedy.

“I want to win every single game,” Harper said. “I’m going to try to come up as clutch as I can in those situations. I love those situations in a game, any of those situations.”

Added Manager Davey Johnson: “We’ve had a lot of injuries to key players, but there’s no let-up in anybody in that locker room, I can tell you that.”

It’s a contagious no let-up that Johnson and players say has been recently exemplified by Harper. On a flyout, Harper was nearly at second base by the time the ball was caught. When he chopped a soft grounder that died in the grass in front of Kennedy in the first inning, Harper was flying down the first base line.

Playing in his first game as the team’s No. 3 hitter, a promotion in the lineup he earned after only four major league games, Harper went 1 for 3. In 16 major league at-bats, Harper has six hits, and four are doubles.

And though he has impacted every game he has been in since his Saturday call-up, The Kid, as Johnson calls him, is still a little green. In the first inning, Kennedy’s throw was wide of first and Harper quickly turned and darted toward second. But Harper was called out, after a Diamondbacks appeal, because he narrowly missed touching first base.

“I saw his foot, it looked like he missed it but thought it was right up against it,” Johnson said. “The umpire showed me his footprint. I thought that was pretty good to see the ball go by the guy and also see the foot.”

Since the start of the season, nine Nationals players have been on the disabled list, and eight are still on it, missing a combined 149 games this season. Morse, Storen and Chien-Ming Wang have yet to play this season. Zimmerman hasn’t played in nearly two weeks.

The injury bug claimed LaRoche, the team’s best hitter with a .311 average, four home runs and 17 RBI, with a sore right oblique muscle, which he injured diving for a ball in Wednesday’s win. Chad Tracy started at first base in his place. While the timetable for his return isn’t yet known, Johnson said LaRoche’s injury isn’t as bad as DeRosa’s and LaRoche could be out “two to three days.”

Through the injuries, the Nationals’ pitching has been key. Detwiler allowed one run on three hits over 61 / 3 innings, walking three batters. He needed only 27 pitches, throwing 23 for strikes, to get through three innings. He retired 12 of the first 14 batters and didn’t allow his first hit until the fifth inning.

After Ryan Mattheus relieved Detwiler in the sixth inning with a runner on second base and one out, fans gave the 26-year-old left-hander a standing ovation. Tyler Clippard and Henry Rodriguez allowed no hits over the final two innings.

“Pitching and defense wins championships,” right fielder Jayson Werth said. “We’ll go with that for now. And once we get healthy, maybe we’ll go with something else.”

For now, that formula also includes Harper, who helped the Nationals snap a five-game skid on Wednesday with two doubles and drove in the winning run the following night with another double.

“He’s a good-looking young hitter,” Johnson said. But quickly, he stopped and corrected himself. “Or a good-looking hitter, period,” he said to himself. “Quit using ‘young.’ ”