Max Muncy’s three-run double highlighted a five-run fifth inning, Shohei Ohtani stole his 39th base of the season and the Los Angeles Dodgers beat the Seattle Mariners 8-4 on Wednesday night to complete their three-game sweep.

Ohtani is just one stolen base and one home run away from becoming the fastest player in major league history to reach 40-40. The Japanese superstar would be the first player in Dodgers history to do so.

The NL West leaders defeated the Mariners 17-7 in the interleague series. The Dodgers won their fourth game in a row and extended their lead over Arizona and San Diego to four games.

“What we did in this series with those starters was a masterpiece,” Dodgers manager Dave Roberts said. “You could argue that the starting staff over there is one of the top two players in baseball. Wearing those guys down and getting them into the bullpen was one of our most impressive three-game series in terms of beating the starter.”

Dodgers starter Jack Flaherty (10-5) allowed two runs – one earned – and five hits in 5 2/3 innings. The right-hander struck out five times and walked once.

The reeling Mariners have lost three straight and eight of nine games, going 1-8 on trips to Detroit, Pittsburgh and LA.

The Dodgers extended their lead to 8-1 with two outs in the fifth inning. Freddie Freeman’s RBI double brought home Ohtani, who hit a single, stole second base and reached third base on a wild pitch by Logan Gilbert.

Freeman scored on Hernández’s RBI single after reaching third base on another wild pitch from Gilbert. Muncy’s double into the right field corner brought in three more runs.

“They have really good pitchers there, arguably the best in baseball, and it felt really good to get some good hits,” said Muncy, who was activated from the injured list earlier this week after missing nearly three months.

Gilbert (7-10) shut down the first six Dodgers before scoring in each of the next three innings. The right-hander allowed eight runs and seven hits in 4 2/3 innings, had seven strikeouts and two walks, and had three wild pitches, all of which resulted in runs.

Will Smith’s sacrifice fly to the warning track in center extended the Dodgers’ lead to 3-1 in the fourth inning. Teoscar Hernández walked, stole second base and reached third base on Gilbert’s wild pitch.

The Dodgers took a 2-1 lead with two outs in the third inning on a hard-hit double to the left corner by Mookie Betts. Kevin Kiermaier reached first base on a fielding error by shortstop Leo Rivas, and Ohtani walked and scored from first base without making a play at the plate.

The Mariners led 1-0 on Dominic Canzone’s sacrifice fly that scored Randy Arozarena, who was hit by Flaherty, then stared down the pitcher and stole second base in the second inning. Arozarena seemed to take offense at being hit by his former teammate’s 2-2 pitch in St. Louis.

“I respect Randy as a player,” Flaherty said. “There’s no reason for me to beat him in that position, and he took offense to it.”

Arozarena flied out in the bottom of the third and never made it to first base while cheering on Flaherty. Both benches were cleared, but the umpires intervened and nothing happened.

When asked what he said to Arozarena, Flaherty replied: “It doesn’t matter. It’s between the lines.”

Fans booed Arozarena when he came on in the sixth inning. Flaherty let him walk and the outfielder dropped his bat and strolled to first base. After the Dodgers’ big fifth inning, Arozarena slowly came in from left field while Hernández came out to take his place, and they talked.

TRAINING ROOM

Mariners: OF Victor Robles (hip flexor strain) sat out after being injured Tuesday when he collided with the wall at center while trying to catch a ball. He will be re-evaluated Thursday.

Dodgers: INF Miguel Rojas was given the day off because of left thigh problems. He is expected back in the lineup Friday. … RHP Blake Treinen was activated after missing 14 games because of right hip discomfort.

Next

Mariners: They have Thursday off before RHP Luis Castillo (10-12, 3.51 ERA) starts Friday against San Francisco.

Dodgers: After a day off, RHP Bobby Miller (1-3, 8.02) starts Friday against Tampa Bay.