The Washington Nationals bench rose to their feet in anger when Bryce Harper was plunked for the second time in the contest with two outs in the eighth.
The Nats bench then rose in delight when Jayson Werth's single seconds later tied it.
But it was Justin Upton who made everyone rise in the bottom of the 10th.
Upton's game-winning one-out solo homer lifted the Atlanta Braves to a 3-2 win over the Nationals in the opener of a three-game series.
Ian Krol (1-1) took over for Drew Storen to start the 10th and induced a groundout off the bat of Jason Heyward to begin the frame. Upton, though, stepped up next and cracked a shot that just crept over the wall in left-center.
"I didn't think it was going to be out ... but it carried enough," Braves manager Fredi Gonzalez said of the game-winning homer.
Upton's blast sent Atlanta to its 17th win in its last 19 tilts and gave the Braves a giant 15 1/2-game cushion over Washington for the top spot in the National League East.
Atlanta starter Alex Wood, the rookie flamethrower with his signature sidewinding delivery, baffled the opposition again. He surrendered just a run on five hits and struck out a career-high nine over 6 1/3 innings in the no- decision.
Scott Downs (2-0) picked up the win with a scoreless top of the 10th.
Washington fell to 3-11 this year against the Braves.
Ryan Zimmerman hit a two-out double in the eighth against Luis Avilan before Avilan drilled Harper with a fastball on the back of his left shoulder. Werth then shot a single through the hole on the right side of the infield to knot the game at 2-2.
"It's not easy losing, that's for sure," Werth said. "It's kind of been the story of the year for us so far. We play just good enough to lose."
Earlier, the Braves opened the scoring with a run in the first and they pushed across another in the third.
With the bases loaded and no outs in the opening frame, Freddie Freeman grounded into a double play to score a run and Anthony Rendon's bad throw on an Upton grounder in the third allowed Paul Janish to score for a 2-0 lead in favor of the hosts.
Washington's Ian Desmond rolled into a twin-killing with runners on the corners in the fourth to get the Nats on the board.
Wood is 2-0 with a 1.78 ERA over his last two starts ... The Braves were 0- for-5 with runners in scoring position, while Washington finished 1-for-10 with RISP.