The session, which started around 4:15 p.m. ET, lasted about 40 minutes, and Acta's message was clear to his players: Let's focus and play smart baseball.
Since their three-game sweep over the Mariners in mid-June, the Nationals have played sloppy defense, made mental mistakes and been unable to hit in the clutch. Acta had decided after Tuesday's game -- in which the Angels pounded the Nationals -- that enough was enough.
He also told his players that they can still compete against high-caliber teams -- like the Angels -- even though they've lost Nick Johnson, Austin Kearns and Ryan Zimmerman to injuries.
"We just wanted to make these guys aware that you can't get complacent," Acta said. "We all know that we miss those guys, but still, we are not throwing Independent League players out there, and I thought we were better than that.
"Let's tight up our defense a little bit. ... Since we don't have our three main guys out there, we still should be able to ... hit the cutoff and make routine plays."
Catcher Paul Lo Duca was the only player who spoke up at the meeting. He told his teammates that they need to work hard every night and be thankful that they are in the big leagues.
"I just said you have to respect your teammates," Lo Duca said. "That's nothing against anybody. Take pride in the game. I'm in a situation here where I'm on the bench now. I can't pout about it. Jesus Flores has played well.
"I'm in a situation where if I have to go to another team, I have to go to another team. But I'm still a National. I need to play, and you respect your teammates by playing hard every game. When you are on a losing team, things get magnified. When you don't hustle balls out, you don't do the little things to win ballgames -- they get magnified."
Looking to score more runs, Acta decided to place Flores, 23, in the cleanup spot for the first time in his career on Wednesday -- and for good reason. Flores is second on the Nationals in RBIs, with 28, but team leader Lastings Milledge, who has 30, has had more than twice as many at-bats.
At first, putting Flores at the No. 4 hole didn't work, as he struck out three times in his first four at-bats. But that fifth at-bat made a difference.
With Elijah Dukes on second and reliever Scot Shields on the mound in the ninth inning, Flores took a 2-1 curveball and singled to right-center field to plate the game-winning run.
"That was a great feeling after having bad at-bats before," Flores said. "I tried to calm down because I knew that I swung at a lot of bad pitches. In that situation right there, I prepared myself to look for that pitch. I was glad that he left it there and I drove it to right field."
Acta continues to be amazed by Flores' repeated success.
"He showed in the last year and a half that he doesn't get rattled," Acta said. "He doesn't care about his age, who's facing him or the situation. He has tremendous knowledge of the strike zone for a kid that we got from Class A ball."
As late as the eighth, it looked like the Nationals had the victory wrapped up and were going to give Tim Redding his seventh win of the season.
With right-hander Ervin Santana on the mound for the Angels in the sixth, the Nationals had the bases loaded when Ronnie Belliard came to the plate. He walked on a 3-2 pitch, sending home Dukes.
Wily Mo Pena was the next hitter, and he singled to right field to bring home Milledge.
But the Angels ended up tying the score in the top of the eighth inning off reliever Luis Ayala. With runners on first and second and one out, Casey Kotchman doubled to right field to bring home Erick Aybar.
Ayala was taken out in favor of closer Jon Rauch, who was able to stop the bleeding. He gave up a sacrifice fly to Howie Kendrick, but then struck out Gary Matthews Jr. to end the inning. Rauch ended up with the victory, his fourth of the season
For one day, at least, Acta's team meeting made a difference.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.