Haren pitched two-hit ball through 7 1/3 innings in a 1-0 victory on Wednesday. Brian Bixler's bunt single in the fourth and Ivan Rodriguez's eighth-inning single were the only hits against the three-time All-Star right-hander.
"Just like hitters have hot streaks, I was rolling there," Haren said. "My command was better. I established my fastball and my split was a little better than it has been. But to be honest, it wasn't that much different than my other outings. And before anyone says it's just the Nationals, keep in mind they'd won 13 of 15 coming into this series."
The 68-year-old Johnson took over the Nationals this week, after the abrupt resignation of Jim Riggleman. It was Johnson's first series in a big league dugout since 2000 with the Los Angeles Dodgers.
"I've loved this team from spring training on, and I love them even more now," Johnson said. "It's a great ballclub. We've just got a few things we've got to straighten out, and we'll be fine.
"It was a tough series, and we got hit with a few injuries. But it's a long season. I told the guys earlier: 'You guys win games, I lose them.' So I'm 0-for-3. I've got three in my column, and I plan on rectifying that."
Despite the loss, the Nationals finished the month 17-10. It's the first time they've had a winning record in June since 2005, the club's first season after leaving Montreal.
"Davey's a good baseball man and he's going to be a good manager of this club," right fielder Jayson Werth said. "I guess you could call this a bump in the road, or however you want to define it. It's a new situation for him, but everybody is comfortable and the transition was smooth. It was a tough series, dropping three here, but we've been playing good baseball."
The Nationals were swept in a three-game set for the third time, all on the road. Philadelphia and Baltimore also did it to them. The Angels swept a three-game set for the second time this season, the other one coming against the White Sox at Chicago.
"It's good just to finish off a series, no matter who it is against," Angels left fielder Vernon Wells said. "We've had a couple of opportunities to do that, and for us to be able to it in our first series at home for a while, it's huge."
Haren (8-5) threw 120 pitches, struck out six and walked one. He lowered his ERA to 2.85 against a patchwork lineup, as Johnson rested Werth, left fielder Laynce Nix, catcher Wilson Ramos and shortstop Ian Desmond -- all of whom played in the first two games.
Werth had a sore left knee and tightness in his hip, Desmond had a sore left quadriceps, Nix had a problem with his right Achilles tendon and Ramos came to the ballpark feeling under the weather. Desmond entered in the fifth as a pinch runner and Werth struck out as a pinch hitter in the seventh after Scott Downs replaced Haren.
Downs got the last two outs in the eighth, and rookie Jordan Walden got three outs for his 18th save in 24 chances after blowing three straight save opportunities in a six-day span. Walden struck out Michael Morse with a runner at third base to end it.
Jordan Zimmermann (5-7) allowed four hits over eight innings in his first career complete game in 38 starts. He struck out four and walked one. The 25-year-old right-hander is 4-2 with a 2.63 ERA over his past 11 outings, and has given up just three home runs in 73 innings during that stretch.
"What a great ballgame. It was one of the better ballgames I've ever seen pitched," Johnson said. "I left Zim out there because he deserved every chance to get a win. We just couldn't get it done. You have to tip your hat to Haren. He pitched a heck of a ballgame also."
The only run came in the fourth inning and was unearned after a throwing error by third baseman Ryan Zimmerman.
Zimmermann, who had walked no more than two batters in any of his previous 15 starts, walked Bobby Abreu to open the fourth. Zimmerman tried for the force at second on Wells' grounder and threw the ball past second baseman Danny Espinosa for an error. Abreu made it to third on the play and scored on Howie Kendrick's double-play grounder.
"I went up against a pretty good pitcher today and he had our hitters off-balance all day," Zimmermann said. "It was a battle for both teams to score some runs. One little mistake, and they got that one run. You never want to walk guys, because most of the time they end up scoring, and that was the ballgame."
Nats outfielder Jerry Hairston Jr. left the game because of a bruised right hand after he was hit by Haren as he tried to check his swing in the fifth inning.
"The initial reports I got, I thought for sure it was broken," Johnson said. "But I haven't gotten the results of the X-rays yet. I thought it hit him in the part of the wrist where the metacarpal is. I've been hit a bunch of times like that."
Washington signed free agent LHP J.C. Romero to a minor league contract and assigned him to Triple-A Syracuse. ... David Eckstein, the shortstop on the Angels' 2002 World Series championship team, stopped by the ballpark to visit his brother, Rick -- the Nationals' hitting coach. ... The Angels are 8-5 against the Washington/Montreal Expos franchise. They haven't played in the nation's capital since Aug. 26, 1971, when they beat Ted Williams' Washington Senators 4-3 in 10 innings at Robert F. Kennedy Stadium.