WASHINGTON — Atlanta Braves left fielder Justin Upton saw the baseball nestle underneath some green wall padding and initially, instead of trying to make a play, threw his arms up and waited for a call from the umpires.

All the while, Washington's Ian Desmond kept running, making it all the way around the bases for an inside-the-park homer, apparently tying the game in the fifth inning.

Hold on, though.

This is a new era in the majors, where all sorts of plays can be reviewed and changed. So Braves manager Fredi Gonzalez challenged the non-call, and Desmond's home run was switched to a ground-rule double after a five-minute delay. Desmond then got caught stealing, capping a significant sequence Friday in Atlanta's 2-1 victory over Washington.

"These umpires, they're good enough," Upton said. "But sometimes they need a little bit of help."

The result spoiled the Nationals' home opener and gave rookie manager Matt Williams his first loss following a 3-0 start.

Williams did not agree with the way the review went, pointing out that Upton did eventually grab the ball and heave it toward the infield.

"One of the reasons we have replay is to make sure that we get the calls right. I have a question with that one, though, because of what happened after the fact," Williams said. "The fact that when he had to, he reached down and threw it in."

Upton said he paused while hoping for an umpire to say the play was dead, but eventually did go get the baseball because shortstop Andrelton Simmons "was panicking, telling me to throw the ball."

Added Upton: "I made the play a little more confusing than it should have been."

Some in the sellout crowd of 42,834 chanted "Home run! Home run!" during the review delay. And after the homer was overturned, fans booed Upton whenever he was involved in the action, whether he was catching a flyout or stepping into the batter's box.

Desmond, meanwhile, was determined to run until someone told him to stop.

"With the replay stuff the way it is now, not going to leave anything to doubt," he said.

As for this season's expanded replay, Desmond said: "Everyone's trying to figure it out."

Desmond chided himself more for the subsequent running gaffe. It was one of a series of problems for Washington on the basepaths: Bryce Harper got caught because of a pitchout on a steal attempt, and Adam LaRoche was thrown out at the plate by Simmons on a relay.

"We need to put pressure on the other team, as long as it's intelligent," Washington's Ryan Zimmerman said. "You don't want to run into outs."

Washington did eventually even the score, but Atlanta's Chris Johnson delivered a go-ahead sacrifice fly in the eighth off reliever Tyler Clippard (0-1).

Luis Avilan (1-0) got one out in the seventh for the win, and Craig Kimbrel earned his third save with a 1-2-3 ninth.

In the eighth, Atlanta's fourth reliever, David Carpenter, put two runners on with no outs. But he came back to strike out Washington's 4-5-6 hitters, LaRoche, Zimmerman and Harper.

"We had him where wanted him ... and just couldn't get the hit when we needed to," Zimmerman said.

Atlanta's first run came on Evan Gattis' homer leading off the fifth against Nationals starter Jordan Zimmermann, who was scratched Thursday because of a fever and upset stomach. A 19-game winner last year, Zimmermann allowed one run and four hits in five innings while striking out nine.

Atlanta right-hander David Hale threw five scoreless innings in his third career start.

In 2013, Atlanta went 13-6 against Washington in 2013 en route to replacing the Nationals as NL East champions.

"Last year is last year. You get a nice pat on the back and it's over with," Gonzalez said. "We play them six series. Every series is important. It doesn't matter if you play them in April of September."

NOTES: Washington's pitchers struck out 14, giving them 53 Ks, two more than the previous high for a season's first four games, according to STATS. ... Washington LF Harper hit sixth and went 1 for 4 with two strikeouts.