SAN DIEGO -- Austin Barnes had the game of his career Friday night at Petco Park and no one will remember it.

Barnes hit a grand slam in the first and a three-run homer in the sixth as the Los Angeles Dodgers routed the San Diego Padres 10-4 to finish the greatest June in franchise history.

But the memory everyone will take from this game is the sight of the two managers -- Dave Roberts of the Dodgers and Andy Green of the Padres -- charging each other to trigger a benches-clearing face-off between the first and second innings. Both were ejected, although no players were.

And it all apparently started with Dodgers starting pitcher Alex Wood making a verbal threat to San Diego's Jose Pirela, who doesn't understand enough English to know what Wood said.

"They were threatening to hit my guy for stealing signs," said Green. "You don't threaten another player. Wood stood on the mound and made an outright threat to Pirela."

That got Green's blood boiling.

Wood's threats led plate umpire Greg Gibson to warn both teams. And after the end of the first, Gibson summoned both managers to cool the situation. It backfired.

Green had some choice things to say about Wood. Roberts responded in defense of his pitcher and it was game on. The two managers actually tried to get at each other. As the discussion grew more heated, Roberts said something to Green as the Padres manager was being led away by another member of the umpiring crew.

Green responded and Roberts charged him, bumping into the San Diego manager and the umpire as players from both teams rushed the field, separated the managers and stood face-to-face between home plate and the Padres dugout.

"I probably could have handled it differently," said Roberts, who was raised in San Diego County and was both a player and a coach with the Padres and actually sought the managerial job before Green was hired -- and he was subsequently hired by the Dodgers. "I probably got too emotional. I didn't appreciate what Green said about my player."

"Dave probably reacted to the last comment I made," said Green, who thought the threat by Wood demanded a stronger response from the umpiring crew.

But the bottom line was that Pirela had no idea he was being threatened by Wood. The 27-year-old Venezuelan speaks minimal English. He spoke Friday night through an interpreter.

"I didn't know what he said," said Pirela, who was on second with a leadoff double in the bottom of the first. "I wasn't stealing signs."

Actually, Wood was accusing Pirela of signaling pitch location to his teammates.

"At first, I thought he might be mad at himself for giving up a double," said Pirela. "I didn't understand what he was saying."

Asked if he was stealing signs, Pirela replied "No."

But second base umpire D.J. Reyburn heard the threat. And Wood repeated the threat to Gibson when the plate umpire went to the mound to change balls.

"Right then, my hands are tied," said Gibson, who then issued the warning. "The managers wanted to discuss it right then. I'm not going to discuss it then. I wanted to get the game moving. Maybe everybody forgets about it."

But at the end of the first, both managers simultaneously approached Gibson.

"It was a strange situation," said Gibson. "I've never been a part of anything like this. For about the first 30 seconds, it was a civil conversation. Then it was between those two. Green took exception to his team being warned. And then Andy said something to Dave and it escalated from there. Roberts was aggressive and went after Andy."

No players were ejected.

On the field, the Dodgers scored seven runs off Clayton Richard in 4 1/3 innings while Wood ran his record to 9-0 -- becoming the first Dodger pitcher to start a season 9-0 since Rick Rhoden in 1976.

The win gave the National League West-leading Dodgers a 21-7 record in June. The 21 wins tied a franchise record for June -- with the 1952 and 1954 Brooklyn Dodgers and 1973 Los Angeles edition -- and the .750 winning percentage is a franchise record for June.

The win also continued the Dodgers' domination of their Southern California division rivals. The Dodgers are 6-1 against the Padres this season and 31-14 against San Diego since the start of the 2015 season.

The game was essentially over after six hitters.

Richard retired the first two hitters he faced before Justin Turner singled. Richard then walked Cody Bellinger and Logan Forsythe before Barnes drove a fastball 387 feet into the left field stands for the first grand slam of his career.

It was the first of three homers hit by the Dodgers.

Turner hit a 403-foot, two-run homer off Richard in the fourth to make it 6-0. And Barnes drove in three runs with his second homer, a 414-foot drive off reliever Jose Valdez, in the sixth to make it 10-1.

Richard gave up seven runs on nine hits and four walks in 4 1/3 innings.

The left-handed Wood, meanwhile, allowed one run on two hits and three walks over six innings.

NOTES: The Padres activated INF Chase d'Arnaud from paternity leave Friday and optioned OF Franchy Cordero back to Triple-A El Paso. ... The Padres also announced that LHP Dillon Overton will be promoted from El Paso to start Saturday's game against the Dodgers. ... The Dodgers gave SS Corey Seager another day off to rest the hamstring he tweaked June 23 .